Biopsy methods

ABSTRACT

Methods and apparatuses for mechanically removing objects from a body. In particular, described herein are thrombectomy methods and mechanical thrombectomy apparatuses for removal of blood clots from within a lumen of a blood vessel.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/907,153, filed Jun. 19, 2020, now U.S. Pat. No. 11,471,176,which is a continuation of U.S. patent application Ser. No. 16/397,089,filed Apr. 29, 2019, now U.S. Pat. No. 11,026,709, which is acontinuation of U.S. patent application Ser. No. 15/291,015 filed Oct.11, 2016, now U.S. Pat. No. 10,271,864, which is a is a continuation ofU.S. patent application Ser. No. 15/043,996 filed Feb. 15, 2016, nowU.S. Pat. No. 9,463,035, which claims the benefit under 35 U.S.C. § 119to U.S. Provisional Patent Application Nos. 62/284,300 filed Sep. 28,2015, 62/284,752 filed Oct. 8, 2015 and 62/245,560 filed Oct. 23, 2015.The foregoing applications are hereby incorporated by reference into thepresent application in their entirety.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

FIELD

The apparatuses and methods described herein relate to mechanicalremoval of objects from within a body. In particular, described hereinare mechanical thrombectomy apparatuses and methods.

BACKGROUND

It is often desirable to remove tissue from the body in a minimallyinvasive manner as possible, so as not to damage other tissues. Forexample, removal of tissue (e.g., blood clots) from the vasculature mayimprove patient conditions and quality of life.

Many vascular system problems stem from insufficient blood flow throughblood vessels. One causes of insufficient or irregular blood flow is ablockage within a blood vessel referred to as a blood clot, or thrombus.Thrombi can occur for many reasons, including after a trauma such assurgery, or due to other causes. For example, a large percentage of themore than 1.2 million heart attacks in the United States are caused byblood clots (thrombi) which form within a coronary artery.

When a thrombus forms, it may effectively stop the flow of blood throughthe zone of formation. If the thrombus extends across the interiordiameter of an artery, it may cut off the flow of blood through theartery. If one of the coronary arteries is 100% thrombosed, the flow ofblood is stopped in that artery, resulting in a shortage of oxygencarrying red blood cells, e.g., to supply the muscle (myocardium) of theheart wall. Such a thrombosis is unnecessary to prevent loss of bloodbut can be undesirably triggered within an artery by damage to thearterial wall from atherosclerotic disease. Thus, the underlying diseaseof atherosclerosis may not cause acute oxygen deficiency (ischemia) butcan trigger acute ischemia via induced thrombosis. Similarly, thrombosisof one of the carotid arteries can lead to stroke because ofinsufficient oxygen supply to vital nerve centers in the cranium. Oxygendeficiency reduces or prohibits muscular activity, can cause chest pain(angina pectoris), and can lead to death of myocardium which permanentlydisables the heart to some extent. If the myocardial cell death isextensive, the heart will be unable to pump sufficient blood to supplythe body's life sustaining needs. The extent of ischemia is affected bymany factors, including the existence of collateral blood vessels andflow which can provide the necessary oxygen.

Clinical data indicates that clot removal may be beneficial or evennecessary to improve outcomes. For example, in the peripheralvasculature, inventions and procedures can reduce the need for anamputation by 80 percent. The ultimate goal of any modality to treatthese conditions of the arterial or venous system is to remove theblockage or restore patency, quickly, safely, and cost effectively. Thismay be achieved by thrombus dissolution, fragmentation, thrombusaspiration or a combination of these methods.

Catheter directed thrombectomy and thrombolysis are commonly perceivedto be less traumatic, less likely to decrease the morbidity andmortality associated with conventional surgical techniques. In recentyears, direct administration of chemical lysing agents into the coronaryarteries has shown to be of some benefit to patients who have thrombosedcoronary arteries. In this procedure, a catheter is placed immediatelyin front of the blockage and a drip of streptokinase is positioned to bedirected at the upstream side of the thrombus. Streptokinase is anenzyme which is able in time to dissolve the fibrin molecule. Thisprocedure can take several hours and is not always successful inbreaking up the thrombus. Furthermore, it can lead to downstreamthrombus fragments (emboli) which can lead to blockage of small diameterbranches. U.S. Pat. No. 4,646,736 discloses a thrombectomy device thatpermits rapid removal of an obstructive thrombus. However, the device ischaracterized by small catheter tip size and thus is unable to exertsignificant total force on clot masses. Also, a clot which is not ingood position of purchase on a vessel wall in the “line of fire” of therotating wire is not fibrinectomized. This is especially true of clotsfloating free in the blood stream, since it is virtually impossible torevolve within these clots in the absence of a constraint such asfingers.

Further disadvantages to this thrombectomy device include the difficultyof keeping the clot in the space above the wire during all degrees ofrotation as the wire is moved sideways during rotation, which issometimes necessary to sweep the arterial lumen. In fact, sweeping outan entire arterial lumen with a rotating wire is virtually impossible inall but the smallest, i.e., less than 1.5 mm diameter, arteries. Anadditional and serious possible disadvantage is that fragments of theclot may be embolized downstream.

Another approach for capturing emboli is described in U.S. patentapplication 2015/0005781. This application describes a catheter with abasket extending from the distal end. An actuator, such as a rod orcable, can be pulled proximally to retract the basket into the catheter.Unfortunately, the basket occludes the inside of the lumen, preventingthe concurrent use with a positioning and/or supporting guidewire, andthe basket must be held in or near the distal end of the catheter.Depending on the stiffness of the material (e.g., clot) being removed,retrieval of the basket often collapses the distal end of the catheter,preventing its use, and the basket can be difficult to pull into thecatheter, particularly when holding a clot. This may result in sheeringthe clot. Finally the basket must be preloaded into the distal end ofthe catheter prior to insertion into the vessel, and preloading may beboth difficult and time consuming, and may risk disrupting the deviceprior to deployment.

Thus, there is a definite need for a thrombectomy device, andparticularly a mechanical thrombectomy device that can be more effectivein removing tissue such as clots from within a body. Described hereinare apparatuses (devices, systems and kit) and methods of using them,that may address the needs and problems discussed above.

SUMMARY OF THE DISCLOSURE

In general, described herein are medical apparatuses, including medicaldevices and systems including these medical devices, and methods ofoperating these medical devices, for collecting objects, including butnot limited to blood clots (thrombi), tissue (biopsies, small tumors,polyps, calcifications, kidney stones, etc.). The apparatuses describedherein typically include an elongate catheter having a lumen and adistal end and with a distal end opening into the lumen. The cathetermay be low-profile neurovascular catheters (e.g., microcatheters,insertion catheters, etc.) having any appropriate diameter (e.g., <1 Fr,1 Fr-6 Fr, 1 Fr-9 Fr, etc.). A flexible tractor assembly or portion(e.g., which may be referred to herein as a flexible tractor tube orsimply a flexible tube) is typically positioned and longitudinallyslideable within the catheter, and arranged so that the distal endregion (“distal tractor region”) doubles back over the distal end of thecatheter. The flexible tube (“tractor tube”) is generally elongate andhollow and configured to slide and invert over the distal end openingwhen a first end of the flexible tube is pulled proximally within thecatheter. The distal end forming the distal tractor region may betubular or not (e.g., it may be formed of strips of material, etc.). Thecombined catheter and flexible tractor assembly also forms a guidewirelumen through the catheter and the flexible tube that is configured topass a guidewire.

In use, a guidewire may be configured to slide through the apparatus(and may form part of the apparatus) to allow positioning and in somevariations support, typically without interfering with the operation ofthe tractor tube drawing an object such as a blood clot into the body ofthe catheter.

In addition to the catheter having a flexible tractor tube that isarranged within the catheter and inverted or doubled over the distal endof the catheter, the apparatuses described herein may include one ormore features or elements that permit these devices to operate within avasculature without collapsing, particularly at their distal ends,despite applying a pulling moment over the distal edge/opening of thepreferably quite soft distal end. Further, these apparatuses may beadapted to minimize the force required to withdraw the distal tractorregion into the catheter and invert over the distal end opening of thecatheter, without damaging or weakening the distal tractor region,preventing a failure mode in which the flexible tractor tube within theapparatus breaks, binds up, jams or tangles on its self or with thecatheter. For example, as will be described in greater detail below, anyof these apparatuses may include a selectively lubricious region at ornear the distal end of the catheter. The catheter end may be shaped toallow inverting of the flexible tractor region of the distal end of thetube. In addition, the end profile of the catheter (e.g., thedistal-most 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, etc.) may have an arrangementof stiffnesses (e.g., durometers) that prevent collapse/buckling of thecatheter. Alternatively or additionally, the flexible tractor tube maybe adapted for “sweeping” as much of the vessel around the catheter tocollect objects from within the vessel while still allowing relativelylow-force retraction into the catheter and inverting over the distal endof the catheter. The tractor portion of the flexible tube, which mayrefer to a distal portion of the tube within the catheter, may generallyinclude a distal expandable (first) end region that is adjacent, eitherimmediately adjacent or separated by a spacer region, to a secondless-expandable (or non-expandable) end region. The second end region isproximal (when both the first end region and the second end regions aredrawn into the catheter) to the first end region. The flexible tractortube may extend all the way through the catheter to a proximal endand/or proximal handle, or it may end before the proximal end of thecatheter and be connected to a puller. The puller may be another,possible less flexible tube, or a wire, rod, string, etc. The flexibletractor tube is generally configured to have a lumen through it (e.g.,central lumen or radially offset lumen) through which a guidewire may bepassed, passing through the apparatus, including the catheter and theflexible tractor tube. The flexible tractor tube may generally beoperated (e.g., pulled proximally and in some variations pusheddistally) while a guidewire is within this lumen.

The apparatus may be pre-loaded for deployment of the distal tractorregion and capture of an object within a vessel, or in some variationsit may be loaded in vivo, after or during positioning a guidewire and/orthe catheter within a blood vessel. For example, in some variations, theapparatus may be adapted for use in vivo by holding the distal tractorregion retracted into the catheter until the catheter is within thevessel, and preferably near the object to be removed. Once positioned,the distal tractor region of the flexible tube within the catheter maybe distally extended from the catheter, expanded to form the captureshape that can be drawn and inverted over the distal end of the cathetereither with or without advancing the catheter distally. Thus, the distaltractor portion may be safely and securely delivered to the necessarysite within the lumen without risk to damage to the apparatus or thebody.

For example, a method of performing a mechanical thrombectomy to removea clot from a blood vessel may include: advancing a distal end of acatheter through the blood vessel towards the clot; exposing a distaltractor region of a tube that is within the catheter from the distal endof the catheter, wherein the distal tractor region comprises anexpandable first end region and a less expandable second end regionproximal to the expandable first end region; allowing the expandablefirst end region to expand within the blood vessel; positioning thedistal end of the catheter so that a distal end region of the catheteris between the less expandable second end region and the expandablefirst end region of the distal tractor region while the expandable firstend region is doubled over the less expandable second end region; anddrawing the clot into the catheter by rolling the expandable first endregion rolls over the distal end of the catheter so that the expandablefirst end region inverts as the expandable first end region is pulledinto the catheter.

The step of advancing the distal end of the catheter through the bloodvessel towards the clot may include advancing over a guidewire, asmentioned. The catheter may be slid distally over the guidewire orextended distally (or retracted proximally) with the guidewire. Theinner (tractor) tube may be held within the catheter (e.g., near thedistal end, a middle region, or near the proximal end) or in somevariations it may be inserted after positioning the catheter within thevessel. The distal end of the catheter may be positioned at, near oradjacent the object to be removed (e.g., the clot), or it may beseparated by a predetermined distance, e.g., to allow space for theapparatus to set up by extending the distal tractor region out of thedistal end of the catheter and expand in preparation for withdrawing theobject into the catheter.

Thus, once positioned, the apparatus may be deployed by exposing thedistal tractor region and positioning the distal end of the catheter andin some variations the guidewire, to allow the object to be captured anddrawn into the catheter. The distal tractor region may be exposed bypulling the catheter proximally while either holding the flexible tubeincluding the distal tractor region stationary (e.g., relative to theblood vessel) and/or by extending the flexible tube distally.

As mentioned, the flexible tube may include a distal tractor region thatincludes a first end region that is expandable. This end region isgenerally porous (e.g., formed of a mesh, knit, woven, or othermaterial, including solid material having multiple openingstherethrough) and adapted to grab the object (e.g. clot) to be removed.This first end region is generally expandable to between about 1.3× andabout 10× the inner diameter of the catheter (e.g., between about 1.5and about 7×, between about 1.5× and about 5×, between about 1.5 andabout 4×, between about 1.5× and about 3×, etc.). This first distal endregion forming the tractor portion is generally adjacent to the secondend region that is less expandable (or not substantially expandable).The second region may extend proximally all the way down the catheter,or partially down the catheter. In general, the first end region of thetractor portion is exposed from out of the catheter and used to capturethe clot or other object; the second end region may be exposed duringpositioning but may otherwise remain within the catheter duringoperation.

Thus, exposing a distal tractor region of a tube that is within thecatheter from the distal end of the catheter may include extending orpushing the distal tractor region out of the distal end of the catheter.In some variations the distal tractor region is pre-formed so that thefirst expandable distal end region is doubled over the second distal endregion; in other variations the first distal end region is in-line,distal to, the less expandable second distal end region. The cathetermay then be moved distally so that a distal end region of the catheter(including the distal end) is extended in a gap radially between theexpanded expandable first end region of the distal tractor region andthe less-expandable second end region.

In any of the variations in which the distal tractor region is pushedout of the distal end of the catheter, e.g., during this initial in vivoset up phase, the flexible tube, and particularly the distal tractorregion, may be configured or otherwise adapted to allow pushing out ofcatheter without binding up. Binding within the catheter of anexpandable tube may occur if the expandable first end region inparticular becomes caught on the inner walls of the catheter, preventingdeployment. In some variations the expandable first end region isconfigured as a mesh tubular member having filaments (e.g. Nitinol,polymeric, etc.) having between about 24 to 144 stands, having athickness of 0.0005 inches to 0.005 in diameter, wherein the meshtubular member extends in a longitudinal axis, further wherein the meshtubular member has a length that is greater than 5 cm, forms a braidangle between crossing strands in a direction of the longitudinal axisof about 35 degrees or less when being pulled and inverted around thedistal end of the catheter and expands to a diameter of greater than 1.5times an inner diameter of the catheter outside of the catheter whenunconstrained. Within this configuration, the tubular member has beenfound to be pushable.

In other variations, when the expandable first distal end region ispushed or extended out of the distal end of the catheter, it may beconfigured (e.g., pre-shaped, shape-set, etc.) to invert over the distalend of the catheter and expand. The catheter may be moved distally,aiding in pushing this expandable first end region of the distal tractorregion proximally relative to the outside of the catheter.

In any of these methods, the distal tractor region may include theexpandable first end region and a less expandable second end regionproximal to the expandable first end region, and the expandable firstend region is permitted to expand within the blood vessel.

Thus, towards the end of the deployment phase, the distal end of thecatheter is typically positioned so that the distal end region of thecatheter is radially between the less expandable second end region andthe expandable first end region of the distal tractor region while theexpandable first end region is doubled over the less expandable secondend region.

Thereafter, an object (e.g., clot) may be drawn into the catheter byrolling the expandable first end region over the distal end of thecatheter so that the expandable first end region inverts as theexpandable first end region is pulled into the catheter.

As mentioned, positioning may include distally advancing the distal endof the catheter so that the distal end region of the catheter is betweenthe less expandable second end region and the expandable first endregion of the distal tractor region.

A guidewire may be used with any of the methods described herein. Forany of the methods described herein may include advancing a guidewirewithin the blood vessel to the clot, wherein advancing the distal end ofthe catheter comprises advancing the catheter over the guidewire throughthe blood vessel until the distal end of the catheter is proximate tothe clot. The guidewire may be inserted into or through the clot, or itmay be positioned just before the clot. The guidewire may be left induring clot removal, or it may be partially or completely withdrawnfirst. For example, any of these methods may include advancing aguidewire within the blood vessel to the clot, wherein advancing thedistal end of the catheter comprises advancing the catheter over theguidewire through the blood vessel until the distal end of the catheteris proximate to the clot, further wherein drawing the clot into thecatheter comprises advancing the catheter towards the clot over theguidewire while rolling the expandable first end region over the distalend of the catheter.

Drawing the clot into the catheter generally includes rolling the distaltractor region (e.g., the expandable first end region) over the distalend of the catheter. The apparatus may also be moved distally duringactuation of the distal tractor region. For example, drawing the clotinto the catheter may include withdrawing the tube proximally (to rollthe distal tractor region over the distal end) and/or withdrawing thetube proximally while advancing the catheter distally.

In any of these methods, drawing the clot into the catheter may includewithdrawing the tube proximally while advancing the catheter distally,wherein the tube is withdrawn at a different rate than the catheter isadvanced. It may be beneficial in some configurations to advance thecatheter distally more rapidly than the tube (distal tractor region) isdrawn proximally. In some variations, the catheter may be advanced moreslowly than the tube (distal tractor region) is withdrawn proximally.Alternatively in some variations, they are moved at the same rate. Therate of motion may be determined for the flexible tube by looking at theproximal motion (e.g., of the second end region) within the catheter.

In general the expandable first end region of the distal tractor regionis expandable and may form a distal-facing mouth or lip that can engagewith an object such as a clot. The mouth of lip of the expandabletractor region may form a tangent angle or roll angle (as describedbelow in greater detail in reference to FIGS. 18 and 21D) with respectto the long axis of the catheter outer diameter (OD) in the range of5-60 degrees and preferable at least 10 degrees (e.g., 10°-60°, 10°-50°,10°-45°, etc.). As long as the roll angle is at least 10 degrees withthe tube is retracted into the catheter, the tube should not bind or jamon the catheter tip. The mesh tube may be constructed by modifying isstiffness to ensure the roll angle in greater than 10 degrees.Alternatively or in combination to maintaining a minimum roll angle itmay be desirable to maintain a physical space or gap between the tubematerial ID and the O.D of the catheter (as described in greater detailin FIG. 18 , below) at the catheters most distal tip. The gap may needto be greater than, e.g., 0.1, mm 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.7mm, 0.8 mm, 0.9 mm, 1.0 mm, etc. to ensure the tube rolls around thedistal end of the catheter when the tube is retracted. The expandedmaterial (e.g., a mesh, woven, braided, kitted, perforated, etc.material) may be allowed to expand within the blood vessel by itself.Thus the expandable first region may be self-expandable. The expandablefirst end region of the distal tractor region may be pre-biased toexpand. In some variation a shape memory material (e.g., shape memoryalloy) is used. In some variations a biasing element is included in orintegral to the expandable first end region to expand so that the distaltractor region. The expandable first end region may expand to makecontact with an intima of the blood vessel. In some variations theapparatus may be configured (e.g., sized, including sizing theexpandable first end region) so that the distal-most end of the distaltractor region makes contact with the vessel lumen. Thus, any of thevariations described herein may additionally or alternatively include abiasing element such as a loop, ring, scaffold, or the like to push theexpandable distal end region open so that it can make contact with thevessel by applying an increased radial force to expand it open. In somevariations this opening bias (loop, helix, ring, etc.) is located at ornear the distal end of the expandable first end region of the distaltractor region.

Any of the variations described herein may include an expandablecatheter tip. For example, in some variation the durometer of thecatheter tip may be sufficiently soft to compress proximally when thedistal tractor region is drawn proximally into the catheter; compressingthe distal tip axially may expand it slightly (e.g., so that it mayflare out) at the distal end.

As mentioned, exposing the distal tractor region of the tube that iswithin the catheter from the distal end of the catheter may comprisepushing the distal tractor region out of the distal end of the catheter.Alternatively or additionally, exposing the distal tractor region of thetube that is within the catheter out of the distal end of the cathetermay comprise pulling the catheter proximally. For example, exposing thedistal tractor region of the tube that is within the catheter from thedistal end of the catheter may comprise pushing the distal tractorregion out of the distal end of the catheter to expose the expandablefirst end region already inverted over the less expandable second endregion.

In some variations, exposing the distal tractor region of the tube thatis within the catheter from the distal end of the catheter comprisesextending the expandable first end region out of the distal end of thecatheter so that the expandable first end region inverts over the distalend of the catheter as the expandable first end region is extended.

The expandable first end region of the distal tractor region may be anyappropriate length, and any portion of this length (all of it, 90%, 80%,70%, 60%, 50%, 40%, etc.) may be exposed during this set-up period. Forexample, in some variations, exposing the distal tractor region of thetube may comprise exposing at least 5 mm of the expandable first end.The expandable first end region may be, e.g. 5 mm or greater (e.g., 6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45,50, 55, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200, 300, 400, 500mm, etc. between about 5 mm and 500 mm, between about any lower value of5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35,40, 45, 50, 55, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200 mm andany larger value of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30,35, 40, 45, 50, 55, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200,300, 400, 500 mm, where the lower value is always lower than the largervalue). In any of these variations, when exposing the distal tractorregion, either just the expandable first distal end region may beexposed out of the catheter (e.g., when pushing the expandable distalend region out distally and allowing it to invert over the distal end ofthe catheter) or both the expandable first distal end region and theless expandable second distal end region may all or partially exposed.For example, exposing at least 1 cm of the expandable first end regionand at least 1 cm of the less expandable second end region. Theexpandable first end region may be inverted (doubled back) over the lessexpandable second end region.

As mentioned, the expandable first end region may comprise anyappropriate material that is both expandable and able to grip the object(e.g., clot). For example the expandable first end region of the distaltractor region may comprise a mesh that is coupled adjacent to the lessexpandable second end region. For example the expandable first endregion may be one or more of: a woven material, a mesh braided material,a knitted material, or a film material with multiple openingstherethrough. The less expandable second end region may be made of thesame material or it may be made of a different material. The lessexpandable second end region may have the same structure (e.g., woven,etc.) or it may have a different structure, including a less-expandablevariation of the structure of the expandable first end region. Forexample the less expandable second end region may be a non-porous (e.g.non-woven, non-knitted, etc. or solid material) or less porous (e.g.,tightly woven, small pore size knitted holes, tight braid). In somevariation the less expandable second end region may include a transitionregion between the expandable first end region (e.g., having anintermediate expandability) and a non-expandable portion of the secondend region. In general, the less expandable second end portion of thedistal tractor region include non-expandable structures and materials.

A method of performing a mechanical thrombectomy to remove a clot from ablood vessel may include: advancing a distal end of a catheter throughthe blood vessel towards the clot; exposing a distal tractor region of atube that is within the catheter from the distal end of the catheter,wherein the distal tractor region comprises an expandable first endregion and a less expandable second end region proximal to theexpandable fist end region and configured so that the expandable firstend region is inverted over the less expandable second end region;allowing the expandable first end region to expand within the bloodvessel so that the distal end region of the catheter is between the lessexpandable second end region and the expandable first end region of thedistal tractor region; and drawing the clot into the catheter byadvancing the catheter distally and withdrawing the tube proximallywithin the catheter so that the expandable first end region rolls overthe distal end of the catheter and inverts as the expandable first endregion is pulled into the catheter.

As mentioned, the expandable first end region may be inverted over theless expandable second end region before exposing the distal tractorregion. Alternatively, exposing the distal tractor region may includeinverting the expandable distal end region over the less expandablesecond end region as the distal tractor region is exposed. In general,exposing the distal tractor region of the tube that is within thecatheter from the distal end of the catheter may include pushing thedistal tractor region out of the distal end of the catheter. Exposingthe distal tractor region of the tube that is within the catheter out ofthe distal end of the catheter may include pulling the catheterproximally.

A method of performing a mechanical thrombectomy to remove a clot from ablood vessel may include: advancing a distal end of a catheter throughthe blood vessel towards the clot; exposing a distal tractor region of atube that is within the catheter out of the distal end of the catheter,wherein the distal tractor region comprises an expandable first endregion and a less expandable second end region, wherein exposingcomprises extending the expandable first end region out of the distalend of the catheter so that the expandable first end region inverts overthe distal end of the catheter as the expandable first end region isextended; allowing the expandable first end region to expand within theblood vessel as it is extended out of the distal end of the catheter sothat a distal end region of the catheter is between the less expandablesecond end region and the expandable first end region; and drawing theclot into the catheter by withdrawing the tube proximally within thecatheter so that the expandable distal end region rolls over the distalend of the catheter, collapses, and inverts as the expandable distal endregion is pulled into the catheter. Exposing the distal tractor regionof the tube that is within the catheter from the distal end of thecatheter may include pushing the distal tractor region out of the distalend of the catheter. Alternatively or additionally, exposing the distaltractor region of the tube that is within the catheter out of the distalend of the catheter may include withdrawing the catheter proximallyrelative to the distal tractor region of the tube.

Also described herein are mechanical thrombectomy devices for removing aclot from a vessel, the device comprising: a catheter having a distalend and a distal end opening, wherein the catheter has an inner diameterand an outer diameter; a distal tractor region of a tube within thecatheter, wherein the distal tractor region comprises an expandabledistal end region and a less expandable distal end region proximal tothe expandable distal end region, the distal tractor region configuredso that the expandable distal end region is inverted over the lessexpandable distal end region; a guidewire lumen through the catheter andthe tube, including the distal tractor region, wherein the guidewirelumen is configured to pass a guidewire; and a proximal handle coupledto the tube and configured to cause relative motion between the catheterand the tube such that the distal tractor region is released from withinthe inner diameter of the catheter so that the expandable distal endregion may expand to a diameter that is greater than the outer diameterso that the catheter may be advanced between the expandable distal endregion and the less expandable distal end region and the tube may bedrawn proximally to pull the expandable distal end region over thedistal end of the catheter so that the expandable distal end regionrolls into the distal end of the catheter, inverts, collapses and isdrawn into the catheter.

For example, a mechanical thrombectomy device for removing a clot from avessel may include: a catheter having a distal end and a distal endopening, wherein the catheter has an inner diameter and an outerdiameter; a tube having a distal tractor region within the catheter,wherein the distal tractor region comprises an expandable distal endregion and a less expandable distal end region that is proximal to theexpandable distal end region, further wherein the expandable distal endregion is biased to invert over the less expandable distal end region asit is exposed from the distal end of the catheter; a guidewire lumenthrough the catheter and the tube, including the distal tractor region,wherein the guidewire lumen is configured to pass a guidewire; and aproximal handle coupled to the tube and configured to cause relativemotion between the catheter and the tube such that the distal tractorregion is released from within the inner diameter of the catheter sothat the expandable distal end region may expand to a diameter that isgreater than the outer diameter and the tube may be drawn proximally topull the expandable distal end region over the distal end of thecatheter so that the expandable distal end region rolls into the distalend of the catheter, inverts, collapses and is drawn into the catheter.

Also generally described herein are mechanical thrombectomy apparatuses.For example, described herein are mechanical thrombectomy apparatus forremoving a clot from a vessel, including: a catheter having a distal endand a distal end opening; a flexible tube extending within the catheterand doubling back over the distal end of the catheter, wherein theflexible tube is configured to slide and invert over the distal endopening when a first end of the flexible tube is pulled proximallywithin the catheter; and a guidewire lumen through the catheter and theflexible tube that is configured to pass a guidewire.

A mechanical thrombectomy apparatus for removing a clot from a vesselmay include: a catheter having a distal end and a distal end opening,wherein the distal end opening has a durometer that is greater than adurometer of a region immediately proximal to the distal end, furtherwherein the distal end opening has a rounded lip profile; a flexibletube extending within the catheter and doubling back over the distal endof the catheter, wherein the flexible tube is configured to invert overthe distal end opening when a first end of the flexible tube is pulledproximally within the catheter; and a guidewire lumen through thecatheter and the flexible tube configured to pass a guidewire. Thecatheter distal end durometer may be greater than 60 A shore hardness orgreater than 40 D shore hardness.

A mechanical thrombectomy apparatus for removing a clot from a vesselthat include: an inner catheter having a distal end and a distal endopening; a flexible tube extending though the catheter and doubling backover the distal end of the inner catheter, wherein the flexible tube isconfigured to invert over the distal end opening when a first end of theflexible tube is pulled proximally within the inner catheter; an outercatheter extending over the inner catheter and flexible tube; alubricious region of the flexible tube extending between a distal end ofthe outer catheter and the distal end opening of the inner catheter,wherein the majority of the flexible tube is not lubricious; and aguidewire lumen through the catheter and the flexible tube configured topass a guidewire.

A mechanical thrombectomy apparatus for removing a clot from a vesselmay include: an inner catheter having a distal end and a distal endopening; a flexible tube extending though the catheter and doubling backover the distal end of the inner catheter, wherein the flexible tube isconfigured to invert over the distal end opening when a first end of theflexible tube is pulled proximally within the inner catheter; areleasable attachment between the flexible tube and an outer surface ofthe catheter, configured to release when the flexible tube is pulledwith a predetermined force (e.g., that is greater than 0.01 N); and aguidewire lumen through the catheter and the flexible tube configured topass a guidewire.

A mechanical thrombectomy apparatus for removing a clot from a vesselmay include: a catheter having a distal end, a distal end opening and aninner diameter; a flexible tube extending through the catheter anddoubling back over the distal end of the catheter, wherein the flexibletube is configured to invert over the distal end opening when a firstend of the flexible tube is pulled proximally within the catheter, theflexible tube having a low Poisson's ratio, such that the flexible tubehas a diameter of greater than half the inner diameter of the catheterwhen pulled proximally within the catheter with sufficient force toinvert over the distal end opening; and a guidewire lumen through thecatheter and the flexible tube configured to pass a guidewire. Theflexible tubes having a low Poisson's ratio may be less than 0.5 or inthe range of 0.05 to 0.5 or 0.1 to 0.3.

As already mentioned above the flexible tube typically includes thedistal tractor region having an expandable first end region and a less-(or non-) expandable second end region proximally adjacent to the firstend region. Thus, the flexible tube may comprise a mesh tube.

In general, the catheters forming part of the apparatuses describedherein are highly flexible, as would be appropriate for the tortiouspaths taken, e.g. by neurovascular catheters. In some variations, theaggregate stiffness of the assembled apparatus (having the flexible tubewrapped over the distal end and ready for operation) is within apredetermined percentage (e.g., within 10%, within 12%, within 15%,within 16%, within 17%, within 18%, within 19%, within 20%, within 25%,within 30%, etc.) of the original stiffness of the catheter without theflexible tube. For example, the flexible tube extending through thecatheter and doubling back over the distal end of the catheter mayincreases the stiffness of a distal 5 cm of the catheter by less than apredetermined percentage (e.g., 15%) of the stiffness of the distal 5 cmof the catheter without the flexible tube extending therethrough anddoubling back over the distal end of the catheter.

In any of the variations described herein, the distal tractor region ofthe flexible tube is adapted to grab an object, e.g., clot. Inparticular, the flexible tube may be porous or have at least one poroussection having a pore pattern having a longitudinal separation betweenpores of less than a predetermined distance (e.g., about 0.005 inches)in width. As used in this example “pores” includes windows, openings,gaps, etc. between strands of mesh (weave, etc.) as well as pores formedthrough a solid sheet of material. In general, for woven (andparticularly braided) expandable first end region materials, smallerfilaments may be better at grabbing, and therefore smaller pore sizesmay be preferred. The optimal sizing may depend on the material,including filament size, pore percentage, size of the spacing of pores,pore diameters, etc. For example, in some variations it is beneficial tohave a porosity of greater than >60% (greater than 70%, greater than75%, greater than 80%, greater than 85%, etc., between 60-95, 65-95,70-95%, etc.) and a fiber diameter (for woven materials) that is <0.005.The effective pore size of the flexible tubular member required to makesure the clot or foreign body is grabbed may range from 50 to 1000micrometers (μm), or in the range of 100-200 μm, 100-300 μm, 100-500 μmor 500-1000 μm. The flexible tubular member may have a variety of poresizes along its length.

In general, as used herein a woven material includes any material formedby weaving multiple strands of material in an interlacing pattern (e.g.,interlacing strands, filaments, lengths of material, etc.). A mesh isone type of woven material. A woven material is typically morestretchable/expandable in certain directions (on the bias directions)depending on the elasticity of the material forming the weave. Wovenmaterials are typically run in parallel or nearly parallel paths. Aknitted material may be more flexible and generally refers to a singlepath or course that is meandering, forming loops that may besymmetrically arranged and interlocking. Woven material may be highlystretchable/flexible. Knitted constructs tend to be less stretchable butyet still highly flexible.

In any of the apparatuses described herein, and particularly thepre-loaded or pre-formed versions, the apparatus may include areleasable attachment between the flexible tube and an outer surface ofthe catheter, configured to release when the flexible tube is pulledwith a force that is greater than a predetermined force threshold. Forexample, the releasable force threshold may be greater than about 0.001N, greater than about 0.005 N, greater than about 0.01 N, greater thanabout 0.03 N, greater than about 0.05 N, greater than about 0.08 N,greater than about 0.1 N, greater than about 0.3 N, greater than about0.5 N, etc.).

In any of the apparatuses described herein, the flexible tube maycomprise a plurality of strips of flexible material, wherein the stripsare arranged in parallel with the long axis of the flexible tube.Alternatively or additionally, in any of these variations, the distalend opening may comprise a plurality of notches or channels into whichfibers or strips forming the flexible tube are drawn as the flexibletube inverts over the distal end opening.

In any of the apparatuses described herein, the flexible tube maycomprise a polymeric tube having a plurality of holes therethrough. Forexample, the flexible tube may comprise a distal end, a proximal end anda body region there between, wherein the body region transitions from amore flexible distal end to a stiffer proximal end.

As mentioned above, in any of the variations described herein, thedistal end of the catheter (e.g., the distal opening region) may beadapted to prevent collapsing when inverting the distal tractor regionover the catheter opening but still be soft enough to provideappropriate use for neurovascular applications. For example, any of theapparatuses described herein may have a durometer at the distal end(e.g., at the distal end opening/rim) that is greater than a durometerof a region immediately proximal to the distal end. Any of these distalend openings may have a rounded lip profile. In general, though thedurometer of the distal end region may decrease (becoming ‘softer’) thedurometer of the very distal end (the opening) may be high. This, alongwith a rounded end shape, may reduce the force needed to invert thedistal tractor region (e.g., the expandable first end region) as it isdrawn into the catheter, while preventing collapse of the distal endregion of the catheter.

Any of the apparatuses described herein may also include a handleadapted to draw the flexible tube proximally relative to the catheter.The handle may be attached or attachable to the catheter and/or theflexible tube and may include separate controls for actuating eachindependently or, more preferably, in a coordinated manner (or togglebetween these two modes). For example, any of these apparatuses mayinclude a drive handle coupled to a proximal end region of the catheter,wherein the drive handle comprises a control configured to coordinateadvancing of the catheter distally while retracting the flexible tubeproximally when actuated.

Any of these apparatuses may also include an outer catheter extendingover the catheter and flexible tube. The outer catheter may extend overthe catheter and the flexible tube and may keep an external portion ofthe distal tractor region (outside of the catheter) collapsed until ithas been delivered. Any of these apparatuses may include a lubriciousregion of the flexible tube extending between a distal end of the outercatheter and the distal end opening, wherein the majority of theflexible tube is not lubricious. This lubricious region may reduce theinitial force required to start actuating the apparatus.

In any of the apparatuses described herein, the flexible tube may beconfigured to invert over the distal end opening when a first end of theflexible tube is pulled proximally within the catheter and the flexibletube may have a low Poisson's ratio such that the flexible tube (whichmay be a mesh tube) may have a diameter of greater than half the innerdiameter of the catheter when pulled proximally within the catheter withsufficient force to invert over the distal end opening.

Any of these apparatuses may include a puller (e.g., an elongate puller)within the catheter and coupled to a distal end of the flexible tube.The puller is typically configured to draw the flexible tube proximally,though in some variation it may also move it distally. For example, anyof these apparatuses may also include an elongate puller within thecatheter and coupled to a distal end of the flexible tube, wherein theelongate puller comprises a hypotube having an inner lumen that iscontinuous with the guidewire lumen though the flexible tube.

As mentioned, in some variations, the flexible tube comprises a softouter mesh that is pushable. For example the distal tractor region (andparticularly the expandable first end region) may be formed from 24 to144 stands, having a thickness of 0.0020 inches or less in diameter,wherein the mesh tubular member extends in a longitudinal axis, furtherwherein the mesh tubular member has a length that is greater than 5 cm,forms a braid angle between crossing strands in a direction of thelongitudinal axis of about 35 degrees or less when being pulled andinverted around the distal end of the catheter and expands to a diameterof greater than 1.5 times an inner diameter of the catheter outside ofthe catheter when unconstrained.

When the flexible tube is formed of strands (e.g., woven, braided, etc.)the strands may be formed of any of the following; monofilament polymer,multifilament polymer, NiTi filament, NiTi tube with radiopaque metalliccenter, Cobalt chromium alloy filament, Cobalt chromium alloy tube withradiopaque metallic center, Nylon, Polyester, Polyethyleneterephthalate, and Polypropylene.

As mentioned, any of these apparatuses may be configured so that theflexible tube (e.g., expandable distal end region) are releasably heldonto the catheter. For example any of these apparatuses may include aretaining ring around a distal end region of the flexible tubeconfigured to releasably hold the flexible tube against the catheter.

In any of these variations, the flexible tube may be shape set to havedifferent diameter when within the catheter after being pulledproximally into the catheter. In general, the flexible tube may includea plurality of woven or one (or more) knitted filaments. In somevariations the entire (or majority of the) flexible tube is formed of awoven or knitted filament(s), and the proximal end of the flexible tubemay form a tapered opening opposite from a filament or bundle offilaments forming a pull wire. Alternatively or additionally, theflexible tube may be formed from a sleeve of polymer having a thicknessless than 0.020 inches, wherein the sleeve comprises a perforationpattern in which the perforations extend through the polymer. Theperforation pattern may comprise perforations having a shaped consistingof one or more of: round holes, rectangular holes and zig-zag shapes.

Any of these apparatuses may include a pull wire coupled to one side ofa proximal end of the flexible tube configured to be drawn proximally topull the flexible tube within the catheter.

In general, the flexible tube may be any appropriate length. Forexample, the flexible tube may be between 3 to 200 cm (e.g., between 3to 150 cm, 3 to 100 cm, 3 to 50 cm, etc.).

In any of the apparatuses described herein, the flexible tube of theapparatus may be configured so that the flexible tube may be retractedinto the catheter by applying less than a predetermined amount of force(e.g., 500 grams of force, 450 grams of force, 400 grams of force, 350grams of force, 300 grams of force, 250 grams of force, 200 grams offorce, 150 grams of force, etc.) to a distal end of the flexible tube.

In any of these variations, the flexible tube may include a taperbetween the first end and a second end of the flexible tube. In somevariations, the flexible tube may extend within the entire length of thecatheter so that a proximal end of the flexible tube is configured to bepulled proximally away from the proximal end of the catheter to slideand invert the flexible tube over the distal end opening.

Any of the apparatuses described herein may also include a vacuumsource. For example any of these apparatuses may include a guidewirevacuum pump coupled to a proximal end of the guidewire lumen andconfigured to apply vacuum therethrough. For example, any of theseapparatuses may include an outer catheter vacuum pump coupled to a spacebetween the catheter and the flexible tube and configured to apply avacuum within a lumen of the catheter between an inner wall of thecatheter and the flexible tube.

As mentioned, the apparatus may include a puller, wherein a distal endof the flexible tube is coupled to a distal end of the puller. An outercatheter may be arranged over the catheter adjacent to a proximal end ofthe flexible tube. Any of these apparatuses may also include a handlehaving a control configured to coordinate advancing of the outercatheter to push the proximal end of the flexible tube distally andpulling the puller proximally to drawn the proximal end of the flexibletube into the catheter. For example, an apparatus as described hereinmay include: a puller, wherein a distal end of the flexible tube iscoupled to a distal end of the puller; an outer catheter slideablyarranged over the catheter coupled to a proximal end of the flexibletube; and a handle having a control configured to coordinate advancingof the outer catheter distally to push the proximal end of the flexibletube distally while pulling of the puller proximally to drawn theproximal end of the flexible tube into the catheter or pulling the outercatheter proximally to pull the proximal end of the flexible tubeproximally while pushing of the puller distally to push the proximal endof the flexible tube out of the catheter.

Also described herein are methods of mechanically removing athrombectomy including: advancing a guidewire at least to the proximalend of a clot in a blood vessel; advancing a thrombectomy (e.g. clotremoval) apparatus distally over the guidewire, wherein the thrombectomyapparatus comprises a catheter having a distal end and a distal endopening and a flexible tube extending along an outer diameter of thecatheter and over the distal end of the catheter, so that the guidewirepasses through a lumen of the catheter and the flexible tube; pullingthe flexible tube proximally from off of the outer diameter of thecatheter and into the catheter lumen so that the flexible tube slidesand inverts over the distal end opening; and drawing a clot into theinverted flexible tube as the flexible tube is drawn into the catheter.

A method of mechanically removing a thrombectomy may include: advancinga guidewire adjacent a clot in a blood vessel; advancing a thrombectomyapparatus distally over the guidewire, wherein the thrombectomyapparatus comprises a catheter having a distal end and a distal endopening and a flexible tube extending along an outer diameter of thecatheter and over the distal end of the catheter, so that the guidewirepasses through a lumen of the catheter and the flexible tube; pullingthe flexible tube proximally from off of the outer diameter of thecatheter and into the catheter lumen over a rounded lip of the distalend opening of the catheter so that the flexible tube slides and invertsover the distal end opening, wherein the distal end opening has adurometer that is greater than a durometer of a region immediatelyproximal to the distal end; and drawing a clot into the invertedflexible tube as the flexible tube is drawn into the catheter.

A method of mechanically removing a thrombectomy may include: advancinga guidewire adjacent a clot in a blood vessel; advancing a thrombectomyapparatus distally over the guidewire, wherein the thrombectomyapparatus comprises an inner catheter having a distal end and a distalend opening, a flexible tube extending along an outer diameter of theinner catheter and over the distal end of the catheter, and an outercatheter securing a distal end region of the flexible tube against theouter diameter of the inner catheter, so that the guidewire passesthrough a lumen of the catheter and the flexible tube; pulling theflexible tube proximally from off of the outer diameter of the catheterand into the catheter lumen so that a lubricious proximal leader regionof the flexible tube slides and inverts over the distal end opening,until a non-lubricious distal region of the flexible tube is drawn intothe inner catheter; and drawing a clot into the inverted flexible tubeas the flexible tube is drawn into the catheter.

A method of mechanically removing a thrombectomy may include: advancinga guidewire adjacent a clot in a blood vessel; advancing a thrombectomyapparatus distally over the guidewire, wherein the thrombectomyapparatus comprises a catheter having a distal end and a distal endopening and a flexible tube extending along an outer diameter of thecatheter and over the distal end of the catheter, so that the guidewirepasses through a lumen of the catheter and the flexible tube; pullingthe flexible tube proximally from off of the outer diameter of thecatheter and into the catheter lumen so that the flexible tube slidesand inverts over the distal end opening; pulling or pushing the flexibletube distally out of the distal end of the catheter so that the flexibletube slides and inverts over the distal end opening and over the outerdiameter of the catheter; and drawing a clot into the inverted flexibletube as the flexible tube is drawn into the catheter.

In any of the methods described herein, the guidewire may be positionedat least partially within the clot in the blood vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIGS. 1A-1H illustrate one variation of an apparatus for mechanicallyremoving an object such as a clot form a body region. FIG. 1A shows acatheter portion of the apparatus; FIG. 1B shows an enlarged view of adistal end (opening) of the catheter; FIG. 1C shows an example of adistal tractor region of a flexible tube (tractor tube), showing theexpandable first end region of the flexible tube in a collapsed(non-expended) configuration, while FIG. 1D shows the same distaltractor region with the expandable first end region expanded. FIG. 1Eshows an assembled mechanical thrombectomy apparatus with the flexibletube extending through the catheter and doubling back over the distalend of the catheter so that the expandable first end region of theflexible tube (forming part of the distal tractor region) is at leastpartially outside of the catheter and in a non-expanded state. FIG. 1Fshows the apparatus of FIG. 1E with the expandable first end regionexpanded. FIGS. 1G and 1H illustrate the use of the apparatus of FIGS.1E and 1F to remove a clot by drawing the flexible tube proximallyand/or advancing the catheter distally towards the clot so that theexpandable first end region inverts as it is drawn into the distal endof the catheter, pulling the clot into the catheter.

FIGS. 2A-2D show variations of flexible tubes (tractor tubes) that maybe part of the apparatuses described herein. FIG. 2A shows the distalend of the flexible tube including the distal tractor region comprisingthe expandable first end region at the distal end, adjacent to aless-expandable second end region. In FIG. 2B the expandable first endregion is formed of a plurality of woven fibers. In FIG. 2C theexpandable first end region is formed of a sheet of material having aplurality of small pores throughout. In FIG. 2D the expandable first endregion is doubled over the less-expandable second end region.

FIGS. 3A-3F illustrate the in vivo deployment and operation of oneexample of a mechanical thrombectomy apparatus. In this example, thedistal tractor region is pushed through the catheter after positioningthe catheter near a clot until the distal tractor region is exposed fromthe distal end of the clot (FIGS. 3A-3D) so that the expandable firstend region expands to the intima of the vessel; the catheter is thenadvanced between the expandable first end region and the less-expandablesecond end region (FIGS. 3D-3E), and the expandable first end region isdrawn into the catheter so that it inverts and pulls the clot into thecatheter (FIGS. 3E-3F).

FIGS. 4A-4F illustrate in vivo deployment and operation of anotherexample of a mechanical thrombectomy apparatus. In this example, theexpandable first end region of the flexible (tractor) tube is deployedafter positioning the catheter portion (FIGS. 4A-4B) by extending theexpandable first end region out of the distal end of the catheter sothat the expandable first end region double-back over the distal endregion of the catheter (FIGS. 4C-4D). Once exposed and deployed, theexpandable first end region may be drawn back into the catheter with orwithout advancing the catheter distally to pull the clot into thecatheter (FIG. 4F).

FIGS. 5A-5E illustrate in vivo deployment and operation of anotherexample of a mechanical thrombectomy apparatus in which the expandablefirst end region is extended distally out of the end of the catheterafter it has been positioned within the vessel near the clot (FIGS.5A-5C). Once the expandable first end region has been extended andallowed to expand within the vessel, the catheter and the rest of theflexible tube within the catheter may be advanced distally (FIG. 5D) sothat the expandable first end region doubled over the distal end asshown. Thereafter the expandable first end region may be drawn back intothe catheter with or without advancing the catheter distally to pull theclot into the catheter (FIG. 5E).

FIGS. 6A and 6B illustrate a mechanical thrombectomy apparatus includinga catheter and flexible tube (tractor tube) extending through thecatheter and doubling back over the distal end of the catheter (formingthe distal tractor region) and an outer catheter or release protectorcatheter over the distal tractor region. FIG. 6A shows the apparatuspositioned near a clot; FIG. 6B shows the apparatus used with aguidewire through the guidewire lumen of the apparatus for positioningand operating the apparatus.

FIGS. 7A-7D illustrate operation of a thrombectomy apparatus as shown inFIGS. 6A-6B, showing positioning the distal end/distal tractor regionadjacent to the clot (FIG. 7A), then pulling the clot into the catheter(FIGS. 7B-7C) and finally removal of the clot and flexible tractor tube(FIG. 7D).

FIG. 8 shows a thrombectomy apparatus including an optional vacuumsource.

FIGS. 9A-9D illustrate operation of a thrombectomy apparatus asdescribed herein in combination with a guidewire. The guidewire may passthrough the clot completely or partially and the apparatus may beactuated over the guidewire, providing enhanced stability and efficacy.

FIG. 10A shows one variation of a handle (proximal) handle for actuatingan apparatus such as the thrombectomy apparatuses described herein. Thehandle may be coupled and may, separately or in a coordinated fashion,actuate movement of the catheter and flexible (tractor) tube, includingthe distal tractor region.

FIG. 10B shows another example of a proximal handle for an apparatus asdescribed herein, which includes controllers for controlling (separatelyor together) actuation of the catheter and/or inner flexible tractortube.

FIG. 11A shows another example of a proximal handle for an apparatusincluding a thrombectomy apparatus as described herein.

FIG. 11B is a mechanical schematic illustrating operation of a handlefor an apparatus as described herein.

FIGS. 12A and 12B illustrate variations in which the expandable firstend region of the flexible tractor tube of the apparatus is releasablysecured to an outer surface of the catheter; prior to actuation of theapparatus, so that the distal tractor region can be drawn into thedistal end of the catheter, the releasable attachment may be detached.In FIG. 12A an outer tubing (e.g., an outer catheter or releaseprotector catheter over the distal tractor region) covers at least theend of the expandable distal end region. In FIG. 12B the expandablefirst end region of the distal tractor region may include a band,adhesive, weld (e.g., frangible adhesive or other attachment), clap,grasper, or the like, releasably securing the expandable first endregion to the outer diameter of the catheter.

FIGS. 13A and 13B illustrate examples of the proximal end region (pullerregion) of the flexible (e.g., tractor) tube of the apparatusesdescribed herein. FIG. 13A shows an example in which the proximal end ofthe tractor tube forms a pull wire that is radially offset from thelumen of the tube; a guidewire may still pass through the lumen of thetube (and catheter) for operation of the device, as shown. FIG. 13Bshows an example in which the pull wire (or rod, member, etc.) is formedof a separate material than the rest of the flexible tractor tube.

FIG. 14 illustrates a distal tractor region including a limitedlubricious region near a proximal end region of the expandable first endregion of the distal tractor region; other portions of the expandablefirst end region may not be lubricious, nor may other portions of therest of the distal tractor region.

FIGS. 15A-15D illustrate flexible (tractor) tubes having shapedexpandable first end regions. In particular, these different expandablefirst end regions may be pre-set to different diameters which may helpdraw in and/or break the clot up within the catheter. FIG. 15A shows afirst example in which the expandable first end regions is coupled to apuller portion by a plurality of pull wires. The expandable first endregions is shown not inverted over the more proximal portion of theflexible tubular member (tractor tube) in these examples. FIG. 15B showsa plurality of expandable end regions connected by a plurality of pullwires that may not be radially expandable. FIG. 15C shows an expandablefirst end region having a plurality of pre-set diameters. FIG. 15D showsan expandable first end region coupled to a more proximal puller portionof the tractor tube by two or more bundles of the filaments forming theexpandable first end region.

FIG. 16 illustrates another example of an expandable first end regionthat includes a plurality of releasable attachments to the outerdiameter of the catheter; these releasable attachments (which may befrangible, elastic, etc.) can be released by applying sufficient forceto allow the distal tractor region to be pulled into the catheter foractuating the apparatus.

FIG. 17 illustrates an example in which the expandable first end regionis loaded (e.g., spring loaded, compressed, etc.) over the outerdiameter of the distal end region of the catheter and releasably lockedor otherwise held in place, e.g. by a reliable attachment; thisreleasable attachment may prevent deployment of the apparatus untilactuation, and the loading of the expandable first end region may makeit easier for the distal tractor region to invert over the distal end ofthe catheter to draw a clot into the apparatus.

FIGS. 18A-18C illustrate examples of expandable first end regions havingdifferent stiffnesses.

FIGS. 19A and 18B illustrate assembly methods for assembling anapparatus as descried herein.

FIGS. 20A and 20B illustrate exemplary profiles of expandable first endregions that may be used as part of a distal tractor region of anapparatus as described herein.

FIGS. 21A-21D show examples of apparatuses used to remove clots. FIG.21A shows an example of an expandable first end region prior to couplingto a catheter. FIG. 21B illustrates the expandable first end regionwithin a vessel (glass tube) being drawn into a catheter by pulling theproximal end of the flexible (tractor) tube. FIG. 21C shows the distalend region of the apparatus including the expandable first end regionsdoubled over the distal end region of the catheter. FIG. 21D illustratesthe apparatus of FIG. 21C drawing a clot into the catheter.

FIG. 22 shows the expandable first end region of FIG. 21D with thecaptured clot after drawing it proximally out of the catheter.

FIGS. 23A-23D illustrate a mechanical thrombectomy apparatus asdescribed herein capturing a blood clot and drawing it into theapparatus.

FIG. 23E illustrates the clot held within the flexible tractor tubeafter the flexible tractor tube has been removed from the catheter(e.g., proximally).

FIG. 24 is another example of an apparatus including a flexible tractormember in which the distal tractor region is formed of a plurality offilaments that are arranged as strips of material (longitudinallyparallel) that are not woven or braided. These strips may be filaments,or tubes, etc.

FIGS. 25A-25F illustrate another variation of a distal tractor region ofa flexible tractor assembly in which the expandable first end region(e.g., the distal end region of the distal tractor region) is formed ofa plurality of filaments or strips, similar to that shown in FIG. 24 ;the distal end of the catheter includes channels, as shown in FIGS.25A-24B; the strips may fit within these channels, as shown in FIGS.25C-25D. FIGS. 25E and 25F show sectional views through FIGS. 25C and25D.

FIGS. 26A and 26B show a variation of the apparatus of FIGS. 25A-25Fwith an outer sleeve (e.g., an outer catheter or release protectorcatheter or other outer sleeve/protector)

FIGS. 27A and 27B show a sectional view through the apparatus of FIGS.26A-26B.

FIG. 28 is an apparatus including a distal tractor region of a flexibletractor assembly having a plurality of longitudinally-parallel(non-woven/braided) filaments or strips in which the distal ends of thefilaments or strips are connected to each other by a distal connector.

FIG. 29 shows a distal tractor region of a flexible tractor assembly inan apparatus in which the longitudinally-parallel (non-woven/braided)filaments or strips include grabbing elements.

FIGS. 30A-30C illustrate example of filaments/strips with grabbingelements. Grabbing elements (and/or filaments including them) may beused as part of any of the variations described herein, including wovenor braided distal tractor regions.

FIG. 31 illustrates a variation in which the distal tractor region isadapted to be reciprocated (e.g., pushed and pulled) so that theexpandable first end region may be draw into and reversed out of thecatheter.

FIG. 32 illustrates another example of an apparatus as described hereinin which the distal-most end of the expandable first end region is fixedto a portion of the distal end of the catheter; the rest of theexpandable first end region is sufficiently elastic/flexible to be drawninto the catheter (pulling a clot with it). The flexible tractorassembly may then be left retracted and the entire apparatus withdrawn.This example may include an optional vacuum.

FIG. 33 is another example of an apparatus in which the puller portionof the flexible tractor assembly is formed of the same material as thedistal tractor region but may be laminated or otherwise reinforced tohave less flexibility/stretchability than the distal tractor region.

FIG. 34 illustrates another example in which the distal tractor regionis adapted to compress the clot when draw into the catheter.

FIGS. 35A-35C illustrate operation of an apparatus as shown in FIG. 34in which the clot is drawn into the catheter by withdrawing theexpandable first end region of the distal tractor region into thecatheter (e.g., pulling on the puller region of the tractor assembly)which compresses the clot (FIGS. 35A-35B); releasing the tractorassembly and/or pushing it distally may further break up the clot andrelease it from the distal tractor region so that it may be suctioned upproximally with a manual or powered vacuum source (FIG. 35C).

FIG. 36 illustrates an example of an apparatus and method of use inwhich drawing the flexible tractor assembly proximally may advance theapparatus distally through the body (e.g., vessel) over a guidewire,which may be treated to engage the distal tractor region.

FIGS. 37A-37C illustrate an apparatus and method of use in which drawingthe flexible tractor assembly proximally may advance the apparatusdistally.

FIGS. 38A and 38B illustrate another variation of an apparatus andmethod of using the apparatus to remove material from within a vessel,wherein the apparatus is an “infinite” tractor mechanism, in which alarge amount of tractor material (e.g., mesh) is stored in an externalholding region, wound-up but dispensable over an extended use.

DETAILED DESCRIPTION

In general, described herein are methods and apparatuses formechanically removing objects from a body. Although these methods andapparatuses may be adapted for use to remove a variety of objects from avariety of regions of the body, they may be particularly well suited forremoval of blood clots from within a lumen of a blood vessel. Thusdescribed herein are mechanical thrombectomy apparatuses (e.g., deviceand systems).

The apparatuses described herein (e.g., mechanical thrombectomyapparatus for removing a clot from a vessel) may be assemblies includingan elongate catheter having a distal end and a distal end opening, and aflexible tractor assembly at least partially within the catheter, wherethe distal end region of the tractor assembly is configured as a distaltractor region that at least partially extends within the catheter anddoubles back over the distal end of the catheter. The tractor assemblymay include a proximate pusher region which is connected to the distaltractor region. The flexible tractor assembly includes an elongate lumenthat is configured to allow passage of a guidewire. The flexible tractorassembly is also configured to slide along the long axis within thecatheter lumen and invert over the distal end opening of the catheterwhen the proximal end region is pulled proximally. The tractor assemblymay be referred to herein as a flexible tractor assembly, flexibletractor portion, flexible tractor tube, or simply a flexible tube, andis typically positioned and longitudinally slideable within thecatheter, and arranged so that the distal end region (“distal tractorregion”) doubles back over the distal end of the catheter.

For example, FIG. 1A shows one variation of a catheter that may formpart of the apparatuses described herein. In this example, the catheter100 includes a distal end region 103 that includes a distal end 105. Thedistal end region may have an increasing softness (measured bydurometer, e.g., shore durometer) except that the very distal tip(distal end 105) may be substantially less soft than the regionimmediately proximate to it. Thus, although the distal tip region (e.g.,the distal most x linear dimensions, where x is 10 cm, 7 cm, 5 cm, 4 cm,3 cm, 2 cm, 1 cm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm) has anincreasing softness/decreasing harness extending from the proximal todistal ends, the very distal end region 107 (e.g., measured as distalmost z linear dimensions, where z is 1 cm, 9 mm, 8 mm, 7mm, 6 mm, 5 mm,4 mm, 3 mm, 2 mm, 1 mm, 0.8 mm, 0.5 mm, 0.3 mm, 0.2 mm, etc., and z isalways at least three times less than x) has a hardness that is greaterthan the hardness of the region immediately proximal to it, and may beas hard or harder than the proximal-most region of the distal tipregion.

The catheter 100 may also be referred to as the inner catheter or thetractor catheter. Any appropriate type of catheter may be used,including microcatheters appropriate for neurovascular use.

In some variations the distal end 105 of the catheter is adapted so thatthe distal tractor region may slide and invert over the distal end ofthe catheter without being caught (binding) or without substantialfriction. For example, in some variations the distal tip (end) may becurved or radiused 109 as shown in FIG. 1B, particularly on the outersurface (e.g., the transition from outer diameter to inner diameter). Insome variations the distal tip includes one or more channels, as shownand described in FIGS. 25A-28 , including channels around thedistal-facing edge, to guide the sliding of the distal tractor region.

FIG. 1C shows an example of a flexible tractor tube 140. In FIG. 1C, thetube is flexible and elongate (having a generally greater length thanthe catheter 101), and includes a distal tractor region 142 thatincludes a distal-most expandable first end region 144 that isconfigured to fold over the immediately proximal region 146, which maybe a less-expandable second end region. In general the expandable distalend region is configured to expand to a radial diameter that is between1.3 and 10 times the diameter of the inner diameter of the catheter whenunconstrained. FIG. 1D shows the expandable distal end region of FIG. 1Cin an expanded configuration. Thus the expandable distal end region maybe biased to expand open. The expandable distal end region may be formedas a mesh, woven or sheet of material and is generally adapted to graspthe object to be removed (e.g., blood clot).

The flexible tractor tube shown generically in FIG. 1C is shown with theexpandable distal end region doubled back over itself (e.g. over themore proximal less-expandable second end region) in FIG. 1E. In FIG. 1E,the expandable distal end region is collapsed, while in FIG. 1F theexpandable distal end region is expanded. In general, the expandabledistal end region may be distinguished from the proximal less-expandablesecond end region, however in some variations the entire flexibletractor tube may comprise and expandable material (e.g., mesh, weave,etc.) that is pushed and/or pulled within the catheter and does notinclude a proximal less-expandable distal end region.

FIGS. 1G and 1H illustrate the removal of a clot using an apparatus suchas the apparatus assembled from the components of FIGS. 1A and 1E. Inthis example the apparatus is configured as a thrombectomy apparatusincluding a catheter 101 and a flexible tractor tube that includes anexpandable distal end region 144 that extends over the distal end regionof the catheter and doubles-over the distal end of the catheter so thatthe expandable distal end region is continuous with an inner proximalless-expandable (in this example, less-expandable includesnon-expandable) second distal end region 146 that extends proximallywithin the catheter and forms an inner lumen that may pass a guidewire.The proximal end of the flexible tractor tube (not shown) may include apusher/puller member that may be a rod or other member that iscontinuous with the distal end region (distal tractor region 140). InFIG. 1G the apparatus is shown positioned and deployed within the vessel160 near the clot 155. The clot may be drawn into the catheter bywithdrawing the distal tractor region 140 into the catheter 101, asindicated by the arrow 180 showing pulling of the inner portion of theflexible tractor tube (e.g., using a handle, not shown) resulting inpulling the expandable distal end region into the catheter distal endand inverting the expandable distal end region so that it is pulled intothe catheter, shown by arrows 182. The distal end of the expandabledistal end region may be “loose” relative to the outer wall of thecatheter, or it may removal attached or in some variations permanentlyattached.

In general, positioning these apparatuses and actuating them may bechallenging because they must be highly flexible, both before actuatingand during operation. For example, in general, the flexible tractor tubemust not increase the stiffness/flexibility of the catheter, andparticularly the distal end region of the catheter too much, or it maybe too difficult and/or dangerous to maneuver, particularly withintortious vessels of the neurovasculature. Described herein are flexibletractor tube portions that increase the stiffness of the last y cm(e.g., distal most 20 cm, 18 cm, 15 cm, 12 cm, 10 cm, 9 cm, 8 cm, 7 cm,6 cm, 5 cm, 4 cm, 3 cm, 2 cm, 1 cm, etc.) of the catheter less than apredetermined percentage (e.g., less than 10%, 12%, 15%, 18%, 20%, 25%,30%, etc.). For example, described herein are flexible tractor tubeportions that pass through the catheter and double back over the distalend of the catheter but increase the stiffness of a distal 5 cm of thecatheter by less than 15% of the stiffness of the distal 5 cm of thecatheter without the flexible tube extending therethrough and doublingback over the distal end of the catheter.

For example, FIG. 2A shows a flexible tractor tube 201. In this example,the flexible tractor tube includes a distal tractor region 242 with anexpandable first end region 244 and a less-expandable second end region246 that is distal to a proximal pusher region 201. The entire flexibletractor tube is hollow and may pass a guidewire (not shown). The variousregions of the flexible tractor tube may be made of the same material(e.g., a woven, braided, etc. filament or filaments) or they may be madeof different materials.

FIG. 2B shows a flexible tractor tube having a distal tractor region, orat least the expandable first end region 244′ formed of a plurality ofwoven fibers. Alternatively the expandable first end region may beformed of one (or more) knitted fibers, or a combination of woven andknitted fibers. The expandable first end region may be biased open (asshown) by a shape-setting property of the fibers or woven/knittedpattern or by the inclusion of one or more biasing members (e.g., rings,springs, bands, filaments, etc.) that tend to bias at least the distalend region of the expandable first end region open.

FIG. 2C illustrates another variation of an expandable first end regionformed of a sheet of material that includes a plurality of openings(e.g., pores, perforations, passages, windows, etc.). These openings maybe any sizes, including non-uniform sizes (e.g. a range of sizes) oruniform sizes. The sizing of these opening through the sheet may dependon the material used, e.g., polymeric material (PTFE), siliconematerials, polyurethanes, shape memory alloys, etc. In some variationsit is beneficial to have a porosity of greater than >60% (greater than70%, greater than 75%, greater than 80%, greater than 85%, etc., between60-95, 65-95, 70-95%, etc.) of the sheet.

In any of these variations, the distal tractor region is configured sothat it may be inverted (e.g., doubled over) itself, as shown in FIG.2D. In some variations the apparatus may be performed so that theexpandable first end region is inverted over the itself and/or over thedistal end region of the catheter, or it may be configured so that itcan be deployed and inverted over the distal end of the catheter in vivo(e.g., within the blood vessel). In general, before the apparatus can beactuated the catheter may be inserted between the expandable first endregion and the region proximal to the expandable first end region on theflexible tractor tube, which may, in some variations, be theless-expandable second distal end region. This space 289 may be heldopen by a biasing member at or near the distal end of the expandablefirst end region. As mentioned, this expandable first end region openingbiasing member may be a ring, band, spring, coil, or the like, and maybe made of a biasing element (e.g., shape-set material, such as a shapememory alloy), rubber or other polymeric material, or the like.

In vivo deployment of the apparatuses described herein may provide anumber of advantages for users operating the apparatus, despiteassociated challenges. FIGS. 3A-3F illustrates one example of athrombectomy apparatus that is configured for in vivo deployment. Inthis example, the apparatus includes a catheter 301 that may bepositioned (as with any of the variations described herein) using aguidewire 313. The guidewire may be extend to or into (or through) theobject to be removed, shown as clot 355 in FIG. 3A within a blood vessel360. The catheter of the apparatus may be inserted with or after theguidewire, and the catheter may be positioned near (e.g., adjacent to orimmediately adjacent to) the clot with or without the flexible tractortube at or near the distal end of the catheter. In FIG. 3A the catheteris positioned after the guidewire has been positioned, and, as shown inFIG. 3B, is removed from the vessel. The guidewire may be a wire,smaller catheter or combination of devices that may be positioned (e.g.,steered) to and/or through the clot. Following positioning of thecatheter, the inner flexible tractor tube 340 including the distaltractor region 342 is pushed through the catheter to the distal endregion of the catheter, as shown in FIG. 3C. In this example the distalend of the flexible tractor tube forming the distal tractor regionincludes an expandable first end region shown as a mesh 344 that isconnected to a proximal less-expandable second end region that iscontinuous with the rest of the flexible tractor tube, at the proximalend (pusher region 305). The braided mesh 344 of the expandable firstend region is pre-inverted over the outside of the tubular second endregion/pusher region in a collapsed (non-expanded) configuration, andcan be slide through the inner lumen of the catheter, and (when theguidewire is left in position or used adjust the position) over theguidewire (not shown). As shown in FIG. 3D, the distal tractor region ofthe flexible tractor tube may then be exposed to the outside of thecatheter by extending (in this example either pushing the flexibletractor tube distally and/or pulling the catheter proximally, allowingthe expandable first end region of the distal tractor region (shown asmesh) 344 to expand along the length of the first end region. In FIG. 3Dthis is shown as a stent-like structure that may expand fully to theintima of the vessel forming a separation between the expandable firstend region and the less-expandable (in this case non-expandable) secondend region 346. In particular the expansion of the first end region maybe greater than 1.3 times the diameter of the inner lumen of thecatheter (e.g., greater than 1.5×, greater than 2×, greater than 2.2×,greater than 2.5×, greater than 3×, greater than 3.5×, greater than 4×,greater than 5×, greater than 6×, greater than 7×, greater than 8×,greater than 9×, greater than 10×, etc.).

In FIG. 3D, the catheter is slid distally between the first and secondend regions of the distal tractor region. The clot may then be removedby withdrawing the expandable first end region proximally into thecatheter either or both by pulling the flexible tractor tube (e.g.,proximal puller region) proximally and/or advancing the catheterdistally. In some variations it may be beneficial to both advance theapparatus and particularly the catheter, while withdrawing the expandedfirst end region and inverting it into the catheter. The catheter may beadvanced more quickly than the flexible tractor tube is withdrawn.

As shown in FIG. 3F, the clot 355 may be drawn in to the catheter withthe expandable first end region.

Another variation of an in vivo deployment method and apparatus is shownin FIGS. 4A-4F. In this example, the self-expanding first end region ofthe flexible tractor tube is configured to self-expand over end of thecatheter as it is pushed out of the catheter so that it will slide overthe distal end of the catheter. As described above for FIGS. 3A-3B, theapparatus may be positioned using a guidewire 413 or the like. In FIG.4A, the catheter 401 is positioned over the guidewire 413 adjacent tothe clot 455 to be removed. In FIG. 4B the guidewire may be (optionally)removed, or (preferably) left in place. The flexible tractor tube 434including the distal tractor region may then be moved distally withinthe catheter and extended with the expandable first end region 444 outof the distal end so that it inverts 466 over the distal end and slideproximally over the distal end region, as shown in FIG. 4C. This processmay be aided by pushing the apparatus distally within the lumen of thevessel, as the expansion of the first end region 444 may help secure itagainst the wall of the vessel, as shown in FIGS. 4D-4E. Once exposed,the expandable first end region may be withdrawn into the apparatus bypulling the flexible tractor tube 434 proximally and/or advancing theassembly (or at least the catheter) distally, as shown in FIG. 4F. Theclot 455 may then be drawn into the apparatus.

FIGS. 5A-5E illustrate another variation of an in vivo deployment andthrombectomy (clot removal) method using a mechanical thrombectomyapparatus. In FIG. 5A, the apparatus 500 including a catheter 501 and aninner flexible tractor tube 534 is advanced (e.g., over a guidewire, notshown) to be near a clot 555. In this example (which may be relevant toany of the methods described herein) the apparatus is positioned withthe flexible tractor member having the un-deployed distal tractor regionalready positioned distally near the distal end region of the apparatus.As shown in FIG. 5B, the expandable first end region 544, which is in acollapsed configuration within the catheter 501 in FIG. 5A, is pushedout of the distal end of the catheter and expands to the walls of thelumen as shown in FIGS. 5B-5C. Once pushed out and expanded, thecatheter and the portion of the flexible tractor tube within thecatheter may be advanced distally, as shown in FIG. 5D, causing theexpandable first end region 544 to invert, doubling over the distal endregion of the catheter 501. By FIG. 5E, the apparatus has been deployednear the clot 555 and may be actuated as already described to remove theclot, but pulling the expandable first end region of the distal tractorregion into the catheter, so that it inverts and draws the clot into thecatheter. The catheter may optionally be simultaneously advanced. Notethat the method of in vivo deployment described above may also be usedto load an apparatus for insertion into a body in order to position thecatheter radially between the expandable first end region and the moreproximal portion of the flexible tractor tube.

FIG. 6A illustrates an example of another variation of a thrombectomyapparatus having a flexible tractor tube 634 with a flexible first(distal) end region 644 formed in this example of a braided (e.g.,woven) or knitted material, where the flexible first end region (tractorregion) is inverted over the distal end of a catheter 601 and attachedto the proximal end region of the flexible tractor tube 634. As in anyof the apparatuses described herein this proximal end region of theflexible tractor tube may be a hypotube, catheter, or laminatedweave/mesh or woven material that is pushable/pullable within thecatheter and is attached at its distal end to the flexible tractorregion (e.g., distal tractor region), including in some variations anexpandable first end region. Note that in some variations the distaltractor region (the first end region) may not be expandable but may bejust flexible.

In FIG. 6A, the first end region of the distal tractor region attachedto the flexible tractor tube is covered by an outer catheter or sleeve(protector) 677. In this example, the apparatus also includes amid-catheter 679 between the inner catheter 601 and the protectorcatheter or sleeve 677. In some variations the flexible first end region644 may be attached to this mid catheter, including removably attachedso that pulling the flexible tractor tube 634 proximally will disengageit and allow the mesh (the flexible first end region 644) to deploy inthe vessel. In the variation shown in FIG. 6A the flexible first endregion 644 is not attached to the middle catheter 679.

Any of the apparatuses described herein, including the apparatus shownin FIG. 6A may be used with (and may include) a guidewire 633 as shownin FIG. 6B. FIGS. 7A-7D illustrate the operation of the apparatus shownin FIGS. 6A-6B to remove a clot 755. In this apparatus the proximal endof the flexible tractor tube 734 may be coupled to a vacuum source (notshown) which may be actuated when withdrawing the tractor tube 734proximally to invert the distal tractor region over the end of thecatheter. In FIG. 7A the apparatus is positioned near the clot 755. InFIG. 7B, the distal tractor region is inverted and pulled into thecatheter by pulling the flexible tractor tube 734 as shown by the arrow.In this example the distal tractor region is not expanded because itremains covered by the outer sleeve 777, as shown in FIGS. 7B and 7C.The apparatus may be advanced distally toward/over the clot either orboth by pushing or by the action of pulling the distal tractor endregion (shown in this example as a mesh 744) proximally to invert itover the distal end of the catheter. Once the clot is removed, theapparatus may be withdrawn and pulled out of the vessel, as shown inFIG. 7D.

As mentioned above, any of these variations may include one or morevacuum sources. FIG. 8 illustrates one example including a vacuum sourceshowing a first optional vacuum source at the proximal end coupled tothe lumen of the flexible tractor tube 834. For example, the couplingwith the vacuum and the tractor tube 834 may be a rotating hemostaticvalue (RHV) as shown. In FIG. 8 a second (optional) vacuum connection ismade between the (optional) outer catheter 877 and the inner catheter801 or an (optional) middle catheter 878. Vacuum may be applied at anyappropriate portion of the method, including during retraction of theflexible tractor rube 834 to remove the clot.

As mentioned, any of the apparatuses described herein may include aguidewire and may leave the guidewire in position during the procedure.FIGS. 9A-9D illustrate a method of removing an object (e.g., clot) whenleaving a guidewire 913 in position. In this example, the apparatus issimilar to the apparatus shown in FIGS. 6A-6B, and may include anoptional vacuum source. In FIG. 9A the distal end of the catheterincluding the inverting portion of the flexible first end region 944 ofthe distal tractor region 944 is placed adjacent to the clot andactuated by pulling proximally to draw the clot into the catheter asshown in FIG. 9B. In this example the clot has been penetrated by theguidewire 913, thus the catheter tip with the inverting tractor regionmay be advanced forward over the guidewire by pushing on the catheter927 and/or by pulling the tractor tube proximally 919. This may becontinued until the entire clot is within the catheter, as shown in FIG.9C.

In any of the variations described herein, the apparatus may include oneor more markers or may be configured for use with one or more contrastagent to assist in visualizing the methods described. Further any ofthese methods may include visualization. Visualization may be indirect(e.g., using fluoroscopy or equivalent techniques) or direct, e.g.,using one optical fibers for direct visualization down the apparatus(e.g., thought the lumen of the apparatus).

In FIG. 9D, the tractor tube with the captured object (e.g. clot) may beremoved proximally from the apparatus and the removed material may beexamined (e.g., via histological/cytological examination). The cathetermay be subsequently or simultaneously removed. As mentioned above, whenremoving the object (e.g., clot) it may be desirable to pull back(proximally) the guidewire at the same time that the flexible tractortube is pulled back proximally (not shown). In some variations, thedistal tractor region (e.g., braided/woven or knitted region) may grabonto the guidewire within the catheter and which may also help propelthe apparatus distally over/toward the clot, as described in more detailin FIGS. 36 and 37A-37C, below.

In general, the rolling effect of the grabber (the distal tractorregion) is activated by the motion of the catheter relative to thedistal tractor region. If the distal tractor region is fixed proximallyand the catheter is advanced, the distal tractor region may have a 1:1grab ratio. If the distal tractor region is pulled though the catheter,the grabbing effect may be amplified. For example when the distaltractor region is pulled back (by pulling the tractor tube) and invertedinto the inner catheter 1 unit to proximally within the catheter as theinner catheter is pushed 1 unit to distally, the grabbing effect isapproximately 2×. If the distal tractor region is withdrawn into theinner catheter proximally two units as the inner catheter is advanceddistally one unit, the grabbing effect may be approximately 3×. Theconcurrent motion of the distal tractor region and the catheter may becoordinated by a handle.

In general, any of the apparatuses described herein may include ahandle. The handle may couple with the flexible tractor tube and/or thecatheter (e.g., inner catheter) and/or any outer catheter (e.g.,protector, sleeve, etc.). The handle may be configured to allowselective, separate actuation of the flexible tractor tube and/or thecatheter and/or coordinate motion of these components. FIGS. 10A and 10Billustrate examples of handles that may be used. In FIG. 10A, the handleincludes a drive mechanism to pull back the tractor tube, and thereforeinvert the distal tractor region over the distal end of the catheterand/or advance the catheter relative to the distal tractor region. InFIG. 10A, the handle include rotatable handle 1001 couled to a catheterdrive 1003. The handle connects to both the catheter 1005 and the innerflexible tractor tube 1009 having a distal tractor region 1011. Thehandle may be configured so that the ratio of the advancing (distally)of the catheter versus the pull (proximally) of the tractor tube may beselected and/or may depend on a thread pitch of the catheter drivethread or other mechanical mechanism.

Another variation of a handle is shown in FIG. 10B. In this example thehandle may be attached to the tractor tube to pull (or push) 1017 thetractor tube and therefore invert the distal tractor region over thedistal end of the catheter, and another portion of the handle may becoupled to the catheter to push/pull the catheter 1015.

FIG. 11A shows another variation of a handle mechanism 1107 configuredto pull the grabber (distal tractor region) of any of the apparatusesdescribed herein by coupling to the proximal end of the tractor tube atan attachment site 1105, and/or advance the catheter by coupling to theproximal end of the catheter. Another example of a handle mechanism isshown schematically in FIG. 11B, showing a levering mechanism 1109 and acoupling to the inner tractor tube that may be fixed or adjustable.

In any of the apparatuses (e.g., mechanical thrombectomy apparatuses)described herein, the distal tractor region may be preloaded in/on thecatheter so that it can be actuated by pulling the tractor rube coupledto the distal tractor region proximally and/or advancing the catheterdistally. In pre-loaded variations in which the distal tractor regionincludes a flexible and/or expandable first end region (e.g., formed ofa mesh and/or weave of material) that is doubled over the distal end ofthe catheter, the apparatus may be adapted to prevent inadvertentdislodging and/or expansion of the first end region before it has beenpositioned at or near the clot.

FIGS. 12A and 12B illustrate examples of releasable attachments for thedistal tractor regions attached to the outside of the catheter. Any ofthese attachments may be released by the application of an appropriateamount of force (e.g. pulling force) applied to the proximal end of theflexible tractor tube. For example in FIG. 12A, the outer distal end ofthe distal tractor region (shown as mesh 1204) is covered by a shoulderor sock extending from an outer catheter or tubing 1203). Similarly inFIG. 12B, the outer distal end of the distal tractor region (shown asmesh 1204) is covered by a separate band, ring, or sock 1209. The distaltractor region may be prevented from collapsing or reducing in diameterwhen tension (e.g. pulling proximally on the tractor tube) by addingfilaments (e.g., in braided or woven variations, additional braidfilaments), by adding a coating, by heat setting to a larger diameter,and/or by adding an axial inter-braiding pull wire.

Any of the variations described herein may include a proximal pull rodor pull wire as part of the flexible tractor tube. Further, the proximalend region of tractor tube may be less flexible than the distal end(distal tractor region). FIGS. 13A and 13B illustrate examples offlexible tractor tubes. In FIG. 13A, the tube includes a proximal taperregion in which the distal tractor region 1305 is formed of a material(e.g., mesh/woven material) that tapers proximally 1307 into a pullwire, leaving room for a guidewire 1309 and permitting the distaltractor region to invert over a catheter. The proximal pull-wire portionmay be formed of the filaments forming the distal tractor region, e.g.,in variations in which the distal tractor region is woven or braided.These filaments may be reinforced, e.g., by other materials such aspolymers that help make it stiffer or more compliant. FIG. 13B showsanother example in which the proximal end of the flexible tractor tubeis formed of a pull wire 1315 that may be a separate material or anextension of the braid wire bundle attached to the distal end of thepull wire and forming the distal tractor region 1317.

Any of the apparatuses described herein may be treated or adapted toreduce the force required to invert the distal tractor region over theend of the catheter. For example in some variations either the distalend may be treated to be lubricious, or all or a portion of the distaltractor region may be treated to enhance laboriousness. For example, insome variations only a portion of the distal tractor region, e.g., theportion that initially interacts/inverts over the distal end of thecatheter is treated; the rest of the distal tractor region is nottreated. FIG. 14 shows an example of such an apparatus. In FIG. 14 , theproximal-most end 1405 of the expandable and/or flexible first endregion (that is positioned outside of the catheter) is treated with alubricous coating or formed of a lubricious material. The remainingportion (not shown to scale) of the first end region is not as lubricous1403. Since the more proximal region 1405 is exposed to the vessel andthe distal end of the catheter, it may more effectively track the targetor allow the apparatus to track the target as well as start invertingover the distal end more effectively. This region may be made lubriciousin any appropriate manner, including but not limited to coatings such ashydrophobic/hydrophilic coatings, and forming or including a morelubricious polymeric material (e.g. PTFE).

In general, any of the distal tractor regions described herein may beadapted to include different profiles, including pre-set to have (e.g.,shape-set) profiles that may more readily slide/move over the distal endand/or grab a clot or other target object for removal. For example,FIGS. 15A-15D illustrate tractor tubes having different distal endprofiles forming different distal tractor regions. In FIG. 15A forexample, the distal tractor region includes a distal-most expandableand/or flexible first end region 1505 that is formed of a braided/meshor woven material that is connected to proximal end of the tractor tubeby a plurality of pull wires. These pull wires 1517 may be formed by thesame wires or filaments forming the braided/mesh or woven distal endregion. FIG. 15B shows another variation in which a plurality ofdiscrete braided/mesh or woven distal end regions are connected by pullwires 1515; these pull wire regions 1515 may be less-expandable and/orflexible than the braided/mesh or woven regions 1516. In FIG. 15C, thedistal end regions are braided/mesh or woven but pre-set to havedifferent diameters. Thus these regions may have different shapes alongtheir length; these shapes may be heat set to better grab or break upclot as they are pulled into the catheter. FIG. 15D illustrates anexample of a braid or stent-like first end region 1521 that is connectedto hypotube or other more proximal end region of the tractor tube 1520by the same filaments or bundles of the same filaments forming thebraided/mesh or woven distal tractor region 1523.

Any of the apparatuses described herein may also or alternativelyinclude a plurality of releasable attachments to the outer surface ofthe catheter securing the distal tractor region (and particularly thedistal end portion) to the outer surface. In FIG. 16 , three rings 1603,16.3′, 1603″ forming releasable attachment are shown securing the distalend of the distal tractor region 1644 to an outside of a catheter 1601.In this example, a polymer coating/film is attached or integrated withthe braid forming the distal tractor region to help prevent it fromsliding or slipping off of the catheter prematurely (e.g., until pulledby a user). The apparatus can include multiple attachments, as shown,radially positioned along the length of the catheter to help it staysecure to the outer diameter of the catheter delivery system. In somevariations these releasable attachments are elastic member (e.g., aurethane ring) but may be frangible, and allowed to break to free thedistal tractor region.

FIG. 17 shows another variation in which the releasable attachment ispositioned so that a portion of the distal tractor region isspring-loaded (biased) to drive it in rolling over the distal end of thecatheter and into the catheter lumen. In FIG. 17 , The distal end of thedistal tractor region 1704 may be secured (fixed, attached or loose butconstrained) and a more proximal end region near the distal end of thecatheter may be releasably secured to the catheter 1707. For example, apolymeric coating or film may be attached to the distal tractor region(shown as a braid 1744 in FIG. 17 ) and coupled to hold a portion of thedistal tractor region 1705 between the distal end 1704 and releasableattachment site 1707 in tension (e.g., compressed). Release of thereleasable attachment 1707 may then apply a force driving the distaltractor region around the distal end of the catheter, helping pull theclot into the apparatus, and reducing the force necessary to invert thedistal tractor region.

As mentioned above, the material forming the distal tractor region may,and in particular the distal-most flexible and/or expandable first endregion may be formed of any appropriate material. For example, thematerial may comprise a fabric, a weave, a knit, a braided, a sewn, atube, and/or a flat sheet. The material may have any appropriatethickness, e.g., between 0.0005 to 0.015″ wall thickness, and may havepores of any appropriate spacing/dimension (porosity) from low to highporosity. All or a portion of the distal tractor region may beradiopaque or radio transparent. In woven, knitted, braided or sewnvariations, the material may be formed of multi- or mono-filaments.Different size filaments can be mixed together (e.g., big and/or small)to change gripping effect by increasing or decreasing fabric surfacetexture. In some variations the material (including the filamentsforming the material) may be polymer based (e.g., PET, Nylon,Polypropylene, PTFE, ePTFE), elastic and non-elastic (e.g., PU,Silicone, rubber, lycra), metal filaments (e.g., Niti, drawn filled Nitiindcluding DFT, i.e., Niti with Pt inner core, steel, stainless steel,cobalt chrome, etc.), and mix of metallic and polymer filaments. Theends of the fabric can be laser cut/welded or free cut. In somevariations all or part of the distal tractor region includes a film orsheet. The film may be between 0.0005 to 0.008″ thick. The film may beformed by tube extrusion or sheet and rolled into a tube. In somevariations the film is yarn reinforced. The film may be slotted (e.g.,may include holes and/or slits cut to improve gripping or sliding intothe catheter. In some variations the film has a textured surface (e.g.,textured inner surface that is exposed when inverted). The film may forma tube having ridges and/or rings (radial rings) and/or lines down thelength, and/or a saw tooth pattern. A textured inner surface my includea mix of big and small filaments, and/or may be formed of more porous,less dense fabrics.

In some variation, the visibility of the grabber element is desirablebut not required throughout. For example, as mentioned above markers maybe located on the device. In some variations it may be desirable to seethe entire structure or proximal and distal end of structure. Forexample, the material could be Nitinol or Nitinol drawn over platinummaterial (DFT) to enhance visibility.

Any of the variations may include a rotational auger element in theinside of any of the braid constructs to assist in pulling the clot backto the hub. As mentioned, any of these apparatuses may include a vacuumsource. The addition of the vacuum to the system may aid the ability ofthe distal tractor region to pull clot/emboli into the catheter. Thevacuum applied may be stead/constant, ramped or pulsatile.

In some variations the apparatus and methods for using them may includea flow stopping proximal balloon (e.g., to be positioned proximal toclot), that may reduce pressure on clot during the procedure.

The apparatuses and methods described herein may be used to capturebiopsy samples (e.g., from breast or any other organs). For example,these apparatuses can be used to remove bigger tissue segments (e.g.,cancer, gallbladders, etc.) when a laproscopic procedure is performed.

When the material forming the distal tractor region is a woven/braidedmaterial, the resulting mesh structure may have a braid length rangingfrom 1 to 100 cm long to around the outer diameter (O.D.) of thecatheter, with a preferred length of between about 3-30 cm.

In any of these variations, the tractor tube and/or catheter (includingthe distal tractor region) may be constructed so the distal tractorregion may be pulled so that the distal tractor region is drawn(inverted) around the outer diameter of the catheter distal end with aminimal force so the catheter tip does not buckle or significant deform(e.g., snake) in the blood vessel, wherein the pull forces are less thanabout: 50 grams, 100 grams, 300 grams, 500 grams, 800 gram, 1000 grams,2 kg, 3 kg, 5 kg, 8 kg, 10 kg, 15 kg, 20 kg, etc.

In variations in which the grabber (distal tractor region) isconstructed as a woven (e.g., braided) structure at least on a distalend (e.g., the expandable and/or flexible first end region), examples ofthe filaments forming the woven structure may include: NiTi, NiTi-PT DFTwire (NiTi tube over Pt inner), PET, PP, Nylon, Algiloy, SS, hybridmaterials. When used, NiTi may be etched to make is very smooth. Thenumber of filament ends may be about: 16, 24, 36, 48, 77, 96, 144 or anynumber between these integers. Any braid construction may be used. Forexample, an exemplary braid construction may include 1 over 1 (1×1),1×2, 2×2, etc. In some variations the filaments forming the woven and/orknitted material comprises a monofilament, e.g., having an outerdiameter (O.D.) size of about: 0.0005″, 0.00075″, 0.001″, 0.0015″,0.002″, 0.003″ or an combination of sizes or diameter size which isbetween the integers list herein. As mentioned, these apparatuses may beadapted for neuro vasculature used, e.g., assuming 2-3 mm vessel innerdiameter (ID). For example, an apparatus appropriate for neurovascularapplications as described herein may include between 36 to 72 ends of a0.001″to 0.002″ polymer braid annealed to 3-7 mm OD. In some variations,the distal tractor region includes 24 braided wires having an OD of0.0005″ by 0.0015″ or 0.002″ of flat Niti wire, annealed on a 2 mmmandrel, braided at a 45 degree angle. Alternatively in one variationthe distal tractor region comprises a braided material formed from 24wires of a 0.002″ thickness Niti wire, annealed on a 2 mm mandrel,braided at a 45 degree angle. In one example, the distal tractor regioncomprises a braided material including 24 wires 0.002″ DFT Niti wire,annealed on a 2 mm mandrel, braided at a 45 degree angle. In oneexample, the distal tractor region comprises a braided materialincluding 8 ends of 0.003″ wire mixed with 8 additional ends of 0.002″Niti wire on a 2 mm mandrel. In one example, the distal tractor regioncomprises a braided material including 16 ends of 0.002″ platinumiridium wire, annealed on a 2 mm mandrel. In one example, the distaltractor region comprises a braided material including 24 ends of PPmonofilament, having an outer diameter of 0.002″ diameter. In oneexample, the distal tractor region comprises a braided materialincluding 12 ends of 0.003″ PP monofilament. In one example, the distaltractor region comprises a braided material including 16 ends of 0.003″PP mono. In one example, the distal tractor region comprises a braidedmaterial including 72 ends, 0.001″ PET or PP, 8 mm mandrel, 90 degreebraid angle, 1×1. In one example, the distal tractor region comprises abraided material including 36 ends, 0.001″ PET or PP, 6 mm mandrel, 75deg braid angle, 1×1. In one example, the distal tractor regioncomprises a braided material including 48 ends, 0.002″ PET or PP, 8 mmmandrel, 90 degree braid angle, 1×1. In one example, the distal tractorregion comprises a braided material including 24 ends, 0.002″ PET or PP,6 mm mandrel, 70 degree braid angle, 1×1.

In variations in which the distal tractor region comprises a mesh, thetubular mesh may be formed from a knit or alternative structure that isconstructed so it's radially compression (change in tubular mesh innerdiameter, ID) experiences a 5-20% reduction in diameter when the meshtractor is pulled axially and around the outside of the catheter tip andinto the catheter ID. This 5-20% mesh diameter reduction, may aid ingrabbing the clot or foreign object when pulling the mesh into thecatheter, without generating so much radially compression force that thetubular mesh binds on the catheter tip when pulled and does not easilyroll around the catheter tip. In contrast a woven mesh may collapsebetween 20-60% within the catheter when drawn proximally, which mayprovide a substantial amount of compression of a clot of other removedmaterial.

In variations in which the apparatus is configured for use in theperipheral vessels (e.g., having between a 4 to 8 mm vessel ID), thedistal tractor region may be configured for this application. Forexample, the distal tractor region may include a braided material having24 ends of PP, 0.009″ PP monofilament formed on a 4 mm mandrel andannealed. The distal tractor region may include a braided materialhaving 48 ends of PP 0.008″ mono, 4 mm mandrel annealed. The distaltractor region may include a braided material having 72 ends 0.006″ PPmono 4 mm mandrel annealed. The distal tractor region may include abraided material having 36 ends of 0.004″ Niti, 4 mm mandrel annealed.The distal tractor region may include a braided material having 48 endsof 0.004″ DFT Niti mandrel annealed.

In variations in which the apparatus is configured as a biopsy device(e.g., having a 4-12 mm sample size), the apparatus may be a wovenmaterial including 72 ends of PP 0.007″ mono formed on a 10 mm mandrel.In some variations, the apparatus (e.g., the distal tractor region) mayinclude 48 ends of 0.004″ Niti formed on a 1 mm mandrel. In somevariations, the apparatus (e.g., the distal tractor region) may include48 ends of PP 0.008″ mono on a 12 mm mandrel.

In any of the variations described herein the apparatus may beconfigured to have a relatively low friction. In particular the distaltractor region may have a low friction to allow it to be more easilyand/or reliably pulled through the catheter when retracting a clot. Asalready mentioned above, any of these variations may include a lubricousmaterial and/or coating including using or coating one or more of thefollowing materials on the grabber (distal tractor region): PET, PP,PTFE, ePTFE. When the material forming the apparatus is a small diameterfilament metallic structures, the filaments may be between 0.0005 to0.003″ in diameter. The material may be Niti, Stainless, MP35n, Ti,Platinum, Platinum Iridum, cobalt chromium allowy etc.

In variations in which the distal tractor region is a mesh (e.g., wovenand/or kitted material), the diameter of the distal tractor regionrelative to the catheter diameter may be depended on the woven/knittedstructure. For example, when braided, the ratio may be between 2 to 1 orgreater; when warp knit, the ratio is between: 1.5 to 1 or greater. Whenformed as a lasered tube, the ratio is between 1.1 to 1 or greater.Similarly for braided tube or tape structures, the braid angle inside ofthe catheter should be between 0 to 45 degrees of the braid angle insidecatheter, and between about 20 to 90 degrees of the braid angle outsidecatheter. In variations in which the distal tractor region includes aknit braid (e.g., a warp knit) tube, the apparatus may include 12 to 16ends per inch. For an apparatus having a 0.0035″ ID catheter: 12 to 16ends of 20-40 D PET multifilament may be used, or 12 to 16 ends of0.0007 to 0.003″ PET or Polypro or PTFE monofilament, or 12 to 16 endsof 0.0007 to 0.002″ NITI, stainless, MP35n, etc.

As mentioned above, in some variations the distal tractor region isformed of ePTFE as a sheet (e.g., formed into a tube or tape). Thismaterial may be thin walled (e.g., between 0.0005 to 0.003″ thick),think walled (between 0.0005 to 0.002″), and may fold/role over cathetertip. The material may include a 0.001 to 0.004″ with lasered patternthat is stent-like.

Other examples of designs for apparatuses including distal tractorregion of different shapes may be a function of catheter ID. Forexample, in some variations the apparatus may select the catheter ID,number of filaments, diameter/length of filaments, stiffness ofbending/rolling stiffness, Poisson's ratio, friction (and/or texture) ofthe inner surface of the grabber, etc. Smaller diameter catheters mayrequire less mesh filaments or smaller ePTFE tube IDS's than largerdiameter catheters. For example, in some variations in which the distaltractor region is braided, the apparatus may include a 0.072″ IDcatheter having a distal tractor region with 24 to 72 ends of 0.0008″ to0.002 Niti wire, braided on a 6 mm mandrel at a 90 degrees braid angle.In some variations the distal tractor region is formed of 24 to 72 endsof 0.0008″ to 0.002 PP monofil, braided on a 6 mm mandrel at a 90degrees braid angle. In some variations the distal tractor region isformed of a knit braid (assume 0.072″ catheter) and may include 16 endsor 40 D PET multifil free warp-knitted, annealed on a 3 mm mandrel. Insome variations the distal tractor region is formed of 16 ends of 0.002″PP monofil warp-knitted, annealed on a 3 mm mandrel. In variationshaving a distal tractor region formed of ePTFe tubes (again, assuming a0.072″ catheter), the distal tractor region may be 0.002″ thick, 3 mmtube. Alternatively, the distal tractor region may be a 0.002″ thick, 3mm tube laser slotted to collapse and grab clot.

As mentioned, in some variations the apparatus is configured to includea gripping inner mesh surface in the distal tractor region. For examplethe apparatus may include a laser slotted ePTFE tube having largerdiameter braid filaments and/or mixed diameter filaments. In somevariations a gripping inner mesh surface may be formed with a knit braidthat is a warp knit formed tube. Such a structure may have a naturalmacro structure to allow mesh rolling and gripping of clot, sincefilaments do not enter catheter ID parallel to catheter, but rather theyare perpendicular or looped relative to catheter long axis. For examplesin which the distal tractor region is formed of an ePTFE laser slotted(sheet of) material, the structure may include slots cut to allowPoisson ratio to effect tube diameter while creating grippy texture tograb clot.

In general, the effectiveness of the distal tractor region in grabbing aclot may be enhanced by using self-expanding and/or stiffer distaltractor region (e.g., self-expanding and/or flexible first end regionsof the distal tractor region). When the first end region of the distaltractor region is formed of a braid, stiffer filaments (e.g., formed ofbigger diameter filaments, stiffer materials, larger number of fibers,etc.) may result in more expanded first end regions of the distaltractor region, as illustrated in FIGS. 18A-18C. In FIG. 18A a softerdistal tractor region does not expand out beyond the OD of the catheterany substantial distance. FIG. 18B shows a slightly stiffer/moreexpandable first end region of the distal tractor region. FIG. 18C showsthe most expandable distal tractor region 1801, which may optimallyexpand to the intima of the vessel 1803.

As shown in FIGS. 18A-18C, the mouth of lip of the expandable tractorregion may form a tangent angle or roll angle (ϕ) with respect to thelong axis of the catheter OD. This angle may be in the range ofapproximately 5° to 60° degrees (e.g., 10°-60°, 10°-50°, 10°-45°,10°-40°, etc., and preferable at least 10 degrees). The inventors havesurprisingly found that, in some variations, having a roll angle of atleast about 10 degrees (e.g., 10°-60°, 10°-50°, 10°-45°, 10°-40°) withthe tube as the tractor region is retracted into the catheter mayprevent binding or jamming on the catheter tip. The mesh tube may bemodified (e.g., at the distal tip or end region), including by modifyingthe stiffness and/or shape of the distal tip, to ensure the roll anglein greater than 10 degrees. Alternatively or in combination tomaintaining a minimum roll angle it may be desirable to maintain aphysical space or gap between the tube material ID and the O.D of thecatheter (see, e.g., FIGS. 18A-18C) at the catheters most distal tip.The gap may need to be greater than 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5mm, 0.7 mm, 0.8 mm, or 1.0 mm to ensure the tube rolls around the distalend of the catheter when the tube is retracted.

In any of these variations, the distal tractor region may be lubricious(e.g., hydrophilic coating, silicone coating, thin urethane or otherthin elastomeric coating) as mentioned above. One or more polymericbraid ends may be included to enhance lubricity (e.g., polypropylene,nylon, etc.). Further, the braid angle may be kept small (e.g., lessthan 70 degrees, 50 degrees, 45 degrees, etc.) to allow better pulling.This angle may be measured when the distal tractor region is rollingaround/over the tip of the catheter. Increasing the number of ends ofthe weave may also prevent locking of the first end region within thecatheter, so that gaps/spaces between the braid elements are smaller andless likely to snag on the catheter tip when rolling the distal tractorregion over the end of the catheter. Any of these apparatuses may alsoinclude an axial element when formed as a braided element that is lesslikely to collapse or reduce in diameter when pulled, and therefore lesslikely to hang up on the catheter opening when rolling over the tip. Itmay also be advantageous to use slightly larger braid filaments whenusing Niti (e.g., >0.0001″ diameter); the greater the diameter, the lesslikely the braid may deform to lock onto the catheter tip. As mentionedabove, in some variations the distal tractor region may be heat set toautomatically roll over the distal end of the catheter when advanceddistally.

FIGS. 19A and 19B illustrate alternative methods for forming thedoubled-back configuration of the distal tractor region. In FIG. 19A,the tubular distal tractor region 1903 may be coupled to a puller/pusher1901 and then inverted over the catheter tip as mentioned above. In FIG.19B, the tubular braid 1905 is attached distally through the braid to awire/puller 1901 and pulled to invert it over the distal end of thecatheter.

In general, the first end region of the distal tractor region may haveany appropriate shape (refer to FIGS. 15A-15D). FIGS. 20A and 20Billustrate examples of tapered woven braids that may form the distaltractor region. In. FIG. 20A, the braid has a tapered side profile thatmay be attached to a puller (proximal end of the flexible tractor tube)and inverted. Any of the braids described herein may include a markerwire (e.g., DFT, gold, Pt, Pt iridium, etc.) to help with visualization(e.g., fluoroscopically). In FIG. 20B, the mesh is tapered more abruptlythan in FIG. 20A.

As described above, in general, any of the catheters described hereinmay be adapted for use with these apparatuses. For example anappropriate catheter may be highly flexible with a good column stiffness(e.g., will not shorten in length when advanced distally). The cathetercan have a high angle braid reinforcing element. For example, thecatheter may have a high angle braid through proximal to distal end(70-85 degrees, small wire Niti, Stainless, cobalt chrome, MP35N, flator round wire), and a lower braid angle for the distal 1 to 5 cm of thecatheter. This will allow the id of the catheter to expand when axialcompression is applied, and/or under an internal expanding force (e.g.,clot).

In general, any of these catheters may include a changingstiffness/compliance. For example, the proximal third (⅓) may bestiffer; the middle section may be less stiff, and the distal 20% (⅕)may be the least stiff. Further, the distal tip of the catheter may havean appropriate radius (curve) as described in FIGS. 1A and 1B. Ingeneral, the radius should be smooth and round, and not square. Inaddition, the distal tip of the catheter may be made of a hard enoughmaterial (˜72 D or harder) to allow braid to roll and not grab onto tip.For example, the catheter tip may have a hard metallic structure toreduce friction (e.g., stainless steel, Pt, etc.). The less the cathetertip compresses/buckles when pulling the distal tractor region, thebetter. In some variations the catheter includes an additionalreinforcement such as a braid reinforcement rather than a coilreinforcement, to prevent braid buckling for the last 5-10 cm of thecatheter. Thus, as described herein, in some variations, the tip of thecatheter may be made of a lubricous and/or hard material to help reducethe braid to catheter tip friction when the braid is pulled or pushedaround the catheter tip. Lubricous materials may include flour-polymerslike PTFE, FEP and/or hydrophilic coatings. Hard materials like Nylons,or metallics like stainless steel, Platinum and PT iridium alloys couldbe used at the tip and fused/attached to softer materials proximally. Ifa hard tip is put on the distal end of the catheter tip it may be shortin length (e.g., <5 mm and preferably <3 mm) so it does not adverselyaffect catheter tracking.

FIGS. 21A-21D show examples of apparatuses used to remove clots. In thisexample, the distal tractor region was formed of a fine Denier PET meshof approximately 72 ends that is 10 mm (expanded) diameter pulled downonto a 0.071″ catheter, as shown in FIGS. 21A and 21B. FIG. 21A shows anexample of an expandable first end region prior to coupling to acatheter. FIG. 21B illustrates the expandable first end region within avessel (glass tube) being drawn into a catheter by pulling the proximalend of the flexible (tractor) tube. FIG. 21C shows the distal end regionof the apparatus including the expandable first end regions doubled overthe distal end region of the catheter. FIG. 21D illustrates theapparatus of FIG. 21C drawing a clot into the catheter.

Another example examined a distal tractor region formed from a 6 mmbraid having 72 ends and 0.001″ diameter filaments rolling into anddoubled over a 0.071″ ID catheter. A ‘medium hard’ 5 mm clot that was 20cm long was successfully removed. FIG. 22 shows the expandable first endregion of FIG. 21D with the captured clot after drawing it proximallyout of the catheter.

FIGS. 23A-23D illustrate a mechanical thrombectomy apparatus asdescribed herein capturing a blood clot and drawing it into theapparatus. FIG. 23E illustrates the clot held within the flexibletractor tube after the flexible tractor tube has been removed from thecatheter (e.g., proximally).

In some variations described herein the distal tractor region is notformed of a woven or knitted material, but is instead composed of stripor bundles of longitudinally arranged (e.g., in parallel ornear-parallel arrangement). For example, FIG. 24 is another example ofan apparatus including a flexible tractor member in which the distaltractor region is formed of a plurality of filaments that are arrangedas strips of material (longitudinally parallel) that are not woven orbraided. These strips may be filaments, or tubes, etc.

FIGS. 25A-25F illustrate another variation of a distal tractor region ofa flexible tractor assembly in which the expandable first end region(e.g., the distal end region of the distal tractor region) is formed ofa plurality of filaments or strips, similar to that shown in FIG. 24 ;the distal end of the catheter includes channels, as shown in FIGS.25A-24B; the strips may fit within these channels, as shown in FIGS.25C-25D. FIGS. 25E and 25F show sectional views through FIGS. 25C and25D. FIGS. 25A, 25C and 25E show side views and FIGS. 25B, 25D and 25Fshow axial views. In this example, the catheter tip includes channels2502 into which the filaments/strips 2503 run. The strips forming thedistal tractor region are attached to the more proximate puller regionof the flexible tractor tube 2505, shown in FIG. 25E.

FIGS. 26A and 26B show a variation of the apparatus of FIGS. 25A-25Fwith an outer sleeve (e.g., an outer catheter or release protectorcatheter or other outer sleeve/protector)

FIGS. 27A-27B show a sectional view through the apparatus of FIGS.26A-26B.

FIG. 28 is an apparatus including a distal tractor region of a flexibletractor assembly having a plurality of longitudinally-parallel(non-woven/braided) filaments or strips in which the distal ends of thefilaments or strips are connected to each other by a distal connector.

FIG. 29 shows a distal tractor region of a flexible tractor assembly inan apparatus in which the longitudinally-parallel (non-woven/braided)filaments or strips include grabbing elements.

FIGS. 30A-30C illustrate example of filaments/strips with grabbingelements. Grabbing elements (and/or filaments including them) may beused as part of any of the variations described herein, including wovenor braided distal tractor regions. Other options for filaments/stripswith grabbing elements may include braided strips, mesh/woven strips,and micro-coils.

In any of these configuration described herein, the apparatus may beadapted to allow reciprocation of the distal tractor region, cyclingfrom outside to inside and back outside of the distal end of thecatheter. For example, FIG. 31 illustrates a variation in which thedistal tractor region is adapted to be reciprocated (e.g., pushed andpulled) so that the expandable first end region may be draw into andreversed out of the catheter. In this example, the tractor tube (puller)3105 is attached to the distal tractor region 3144 that may be attached(and in some variations is not attached) to a second catheter 3109 overthe inner catheter 3101. The mid-catheter 3109 can be coupled to thepuller 3105 and the two reciprocated together so that the braidreciprocated back and forth inside of the catheter 3101. This may helpbreak up a clot, which may be particularly when used with suction.

FIG. 32 illustrates another example of an apparatus as described hereinin which the distal-most end 3205 of the flexible first end region ofthe distal tractor region is non-releasably fixed to the distal end ofthe outside of the catheter 3201; the rest of the expandable first endregion 3209 is sufficiently elastic/flexible to be drawn into thecatheter (pulling a clot 3255 with it). The flexible tractor assemblymay then be left retracted and the entire apparatus withdrawn. Thisexample may include an optional vacuum 3260.

FIG. 33 is another example of an apparatus in which the puller portion3305 of the flexible tractor assembly is formed of the same material asthe distal tractor region 3344 but may be laminated or otherwisereinforced to have less flexibility/stretchability than the distaltractor region.

FIG. 34 illustrates another example in which the distal tractor region3444 is adapted to compress the clot 3455 when draw into the catheter3401. FIGS. 35A-35C illustrate operation of an apparatus as shown inFIG. 34 in which the clot 3455 is drawn into the catheter by withdrawingthe expandable first end region of the distal tractor region into thecatheter (e.g., pulling on the puller region 3505 of the tractorassembly) which compresses the clot (FIGS. 35A-35B); releasing thetractor assembly and/or pushing it distally may further break up theclot and release it from the distal tractor region so that it may besectioned up proximally (FIG. 35C).

FIG. 36 illustrates an example of an apparatus and method of use inwhich drawing the flexible tractor assembly proximally may advance theapparatus distally through the body (e.g., vessel) over a guidewire,which may be treated to engage the distal tractor region. In thisexample, the apparatus may be configured to pull the inner tractor tube(catheter 3605) which has the mesh forming the distal tractor region3644 attached to its distal end and inverting over the distal end of thecatheter 3601. Pulling the flexible tractor tube 3605 makes the braidroll over the opening of the catheter 3601. The mesh/braid forming thedistal tractor region (e.g., the first end region of the distal tractorregion) is constructed to collapse in diameter when tensile loads areapplied to this structure and lock/grab onto inner wire (guidewire3677). This inner guidewire may have a tacky, rough or knobby surfaceaid mesh/braid grabbing onto wire. As the mesh/braid grabs onto theguidewire, the tractor tube, as a reactionary force, will be drivenforward in the vessel. Alternatively the user will be able to easilyadvance outer catheter 3601 forward through vessel while pulling back onthe tractor tube.

FIGS. 37A-37C illustrate another apparatus and method of use in whichdrawing the flexible tractor assembly proximally may advance theapparatus distally. In FIG. 37A, the distal tractor region 3744 isattached to a middle catheter 3703 (an optional outer catheter 3705 maybe included) and the opposite end of the distal tractor region 3744 isbonded to the distal end of the inner catheter 3701 within the innerdiameter of this catheter. In FIG. 37B the inner catheter is advanceddistally, expanding the distal tractor region both laterally andforward. As shown in FIG. 37C, the outer and inner catheters may then bepushed distally to move the apparatus more distally.

In some variations the distal and flexible tractor region may be heldpre-loaded outside of the catheter, e.g., in a roll or bundle, over thedistal end region of the catheter, so that it can be gradually pulledout of the external storage region and rolled and inverted over thedistal end of the catheter. An example of one such variation is shown inFIGS. 38A and 38B. this exemplary apparatus may be used to removematerial from within a vessel as shown in FIG. 38B, and may be referredto as an “infinite” tractor mechanism because a large amount (e.g.,greater than 50 cm, greater than 60 cm, greater than 70 cm, greater than80 cm, greater than 90 cm, greater than 100 cm, greater than 150 cm, 200cm, greater than 300 cm, greater than 400 cm, greater than 500 cm, etc.)of tractor material (e.g., mesh) may be stored in an external holdingregion, wound-up but dispensable over an extended use.

In FIG. 38A, the apparatus may include the catheter (inner catheter)3811 and the distal tractor region 3806 is formed of a mesh that isrolled up 3803 in a housing region 3813 proximal to the distal end ofthe catheter. The clot 3805 may be drawn into the catheter by pullingthe distal tractor region proximally within the catheter. Because agreat deal of distal tractor region may be stored and withdrawnproximally, this variation may be useful for very long procedures orwhere there is a lot of material to be removed.

This variation may allow a user to unroll a long length of mesh, whichmay be advantageous for more rigid tools, such as, for example, a rigidhypotube during surgery, for example, removing fat in a liposuctionprocedure, removing clot in an intracerebral hemorrhage or a largerperipheral vascular clot.

As mentioned above, in any of the variations described herein, thedistal tractor member may be a woven (e.g., knit) or braided meshmaterial. The mesh may be a knit material, including, for example a weftknit, circular knit, warp braid knit, and/or braid knit.

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. Incontrast, when a feature or element is referred to as being “directlyon” another feature or element, there are no intervening features orelements present. It will also be understood that, when a feature orelement is referred to as being “connected”, “attached” or “coupled” toanother feature or element, it can be directly connected, attached orcoupled to the other feature or element or intervening features orelements may be present. In contrast, when a feature or element isreferred to as being “directly connected”, “directly attached” or“directly coupled” to another feature or element, there are nointervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.For example, as used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, steps, operations, elements, components, and/orgroups thereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

Although the terms “first” and “second” may be used herein to describevarious features/elements (including steps), these features/elementsshould not be limited by these terms, unless the context indicatesotherwise. These terms may be used to distinguish one feature/elementfrom another feature/element. Thus, a first feature/element discussedbelow could be termed a second feature/element, and similarly, a secondfeature/element discussed below could be termed a first feature/elementwithout departing from the teachings of the present invention.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” and “comprising” means various components can be co-jointlyemployed in the methods and articles (e.g., compositions and apparatusesincluding device and methods). For example, the term “comprising” willbe understood to imply the inclusion of any stated elements or steps butnot the exclusion of any other elements or steps.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about” or “approximately,” even if theterm does not expressly appear. The phrase “about” or “approximately”may be used when describing magnitude and/or position to indicate thatthe value and/or position described is within a reasonable expectedrange of values and/or positions. For example, a numeric value may havea value that is +/−0.1% of the stated value (or range of values), +/−1%of the stated value (or range of values), +/−2% of the stated value (orrange of values), +/−5% of the stated value (or range of values), +/−10%of the stated value (or range of values), etc. Any numerical valuesgiven herein should also be understood to include about or approximatelythat value, unless the context indicates otherwise. For example, if thevalue “10” is disclosed, then “about 10” is also disclosed. Anynumerical range recited herein is intended to include all sub-rangessubsumed therein. It is also understood that when a value is disclosedthat “less than or equal to” the value, “greater than or equal to thevalue” and possible ranges between values are also disclosed, asappropriately understood by the skilled artisan. For example, if thevalue “X” is disclosed the “less than or equal to X” as well as “greaterthan or equal to X” (e.g., where X is a numerical value) is alsodisclosed. It is also understood that the throughout the application,data is provided in a number of different formats, and that this data,represents endpoints and starting points, and ranges for any combinationof the data points. For example, if a particular data point “10” and aparticular data point “15” are disclosed, it is understood that greaterthan, greater than or equal to, less than, less than or equal to, andequal to 10 and 15 are considered disclosed as well as between 10 and15. It is also understood that each unit between two particular unitsare also disclosed. For example, if 10 and 15 are disclosed, then 11,12, 13, and 14 are also disclosed.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims.

The examples and illustrations included herein show, by way ofillustration and not of limitation, specific embodiments in which thesubject matter may be practiced. As mentioned, other embodiments may beutilized and derived there from, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof this disclosure. Such embodiments of the inventive subject matter maybe referred to herein individually or collectively by the term“invention” merely for convenience and without intending to voluntarilylimit the scope of this application to any single invention or inventiveconcept, if more than one is, in fact, disclosed. Thus, althoughspecific embodiments have been illustrated and described herein, anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

1. (canceled)
 2. A method of removing material from a body, the methodcomprising: positioning a distal end of a biopsy apparatus within abody, wherein the biopsy apparatus comprises a first catheter that isslideably disposed within a second catheter, and wherein an invertingsleeve is coupled at a first end to a distal end region of the firstcatheter and at a second end to a distal end region of the secondcatheter; advancing the first catheter distally relative to the secondcatheter to invert the inverting sleeve so that the inverting sleeveextends distally out of the second catheter and against a wall of thebody; and capturing a biopsy sample from the body with the invertedinverting sleeve.
 3. The method of claim 2, further comprisingwithdrawing the first catheter proximally to draw the inverting sleeveback into the second catheter with the captured biopsy sample.
 4. Themethod of claim 3, further comprising removing the biopsy apparatus fromthe body after withdrawing the inverting sleeve into the secondcatheter.
 5. The method of claim 2, further comprising pushing the firstand second catheters distally to move the inverting sleeve distally andagainst the wall of the body.
 6. The method of claim 2, wherein theinverting sleeve comprises one or more of: a woven material, a meshbraided material, a knitted material, or a film material with multipleopenings therethrough.
 7. The method of claim 6, wherein the invertingsleeve comprises a knitted material.
 8. The method of claim 2, whereinthe inverting sleeve has a length of greater than 5 cm.
 9. The method ofclaim 2, wherein the inverting sleeve is configured to expand to greaterthan 1.5 times an inner diameter of the second catheter when theinverting sleeve is outside of the second catheter.
 10. The method ofclaim 2, further comprising advancing the biopsy apparatus out of athird catheter before advancing the first catheter distally.
 11. Themethod of claim 2, wherein the biopsy comprises tumor tissue.
 12. Amethod of removing sample material from a body, the method comprising:positioning a distal end of a biopsy apparatus within the body, whereinthe biopsy apparatus comprises a first catheter slideably disposedwithin a second catheter, and wherein an inverting sleeve is coupled ata first end to a distal end region of the first catheter and at a secondend to a distal end region of the second catheter; advancing the firstcatheter distally to invert the inverting sleeve so that the invertedinverting sleeve extends distally out of the second catheter andlaterally against a wall of the body; capturing a biopsy sample from thebody with the inverted inverting sleeve; and removing the biopsyapparatus from the body with the captured biopsy sample.
 13. The methodof claim 12, further comprising withdrawing the first catheterproximally to draw the inverting sleeve back into the second catheterwith the captured biopsy sample.
 14. The method of claim 12, furthercomprising pushing the first and second catheters distally to move theinverting sleeve distally and against the wall of the body.
 15. Themethod of claim 12, wherein the inverting sleeve comprises one or moreof: a woven material, a mesh braided material, a knitted material, or afilm material with multiple openings therethrough.
 16. The method ofclaim 15, wherein the inverting sleeve comprises a knitted material. 17.The method of claim 12, wherein the inverting sleeve has a length ofgreater than 5 cm.
 18. The method of claim 12, wherein the invertingsleeve is configured to expand to greater than 1.5 times an innerdiameter of the second catheter when the inverting sleeve is outside ofthe second catheter.
 19. The method of claim 12, further comprisingadvancing the biopsy apparatus out of a third catheter before advancingthe first catheter distally.
 20. The method of claim 12, wherein thebiopsy comprises tumor tissue.
 21. A method of performing a biopsy toremove sample material from a body, the method comprising: positioning adistal end of a biopsy apparatus within a body, wherein the biopsyapparatus comprises a first catheter slideably disposed within a secondcatheter, and wherein an inverting sleeve comprises a flexible woventube coupled at a first end to a distal end region of the first catheterand at a second end to a distal end region of the second catheter;advancing the first catheter distally to invert the inverting sleeve andadvance the inverting sleeve distally out of the second catheter,wherein the inverting sleeve expands laterally against a wall of thebody; capturing a biopsy sample from the body with the invertedinverting sleeve; withdrawing the first catheter proximally to pull theinverting sleeve and the captured biopsy sample back into the secondcatheter; and removing the biopsy apparatus from the body.